“To those who ask me ‘Why do you wish to eradicate measles?’” … “Because it is there.”… “ and it can be done.”..

Are we following the right herd?

Fig 1: Measles: Are we following the right herd?

…Measles immunity as estimated for the United States (and presumably, most industrialised nations would be broadly comparable), shows that in the pre-vaccine era that almost everyone was naturally immunised prior to the greater availability of vaccines to prevent the circulation of Measles.

(This article is based upon a new book: A Lesser-Known History of How Nature Does Mass Immunization A Whole Lot Better Than Us!: Don't Count Your Children 'til they've Had The Pox, by A. Parent. Also note that all the quotes are referenced with clickable links at the end of this article).

Epidemiology and Prevention of Vaccine-Preventable Diseases

Before a vaccine was available, infection with measles virus was nearly universal during childhood, and more than 90% of persons were immune by age 15 years…

CDC (2015, 209)


Now, as we can tell from these estimated natural immunity statistics, it seems that hardly a child born in the pre-vaccine era had grown to maturity without having the Measles and therefore, at a population (community immunity) level, almost everyone had become immune to death and disabilities from having been naturally exposed to the Measles virus as children. It was in this context that we see the beginning of our efforts to eradicate the Measles as indicated in the following excerpted article.

Vaccination Before the Measles-Mumps-Rubella Vaccine


Any decision to begin mass measles vaccination in the early 1960s thus involved numerous uncertainties. Was the disease serious enough? Would parents feel it worth having their children vaccinated? And if mass vaccination did seem justified, should the live or the killed vaccine (or a combination of both) be used?

In the United States, experience with the polio vaccines played a major role in shaping the consensus that gradually emerged.

…Approximately 15 million children were given one of the new measles vaccines starting with their licensing in 1963 and continuing until mid-1966, and the reported incidence of the disease fell by half… On the basis of this success, with material and financial support from the Centers for Disease Control and Prevention, and inspired by the social and political climate of the time, in 1967 a campaign was launched to eliminate measles from the United States…

Mass measles immunization began in Britain in 1968. In Sweden it began in 1971 and in the Netherlands not until 1976.

Hendriks, J., & Blume, S. (2013)


As you can see from the excerpt above, the vaccine was made widespread and Measles became yet another vaccine-preventable disease. Other regions followed suit at varying times – some rather late as indicated above, but none as late as Ireland. Ireland was the latecomers to the anti-Measles party. It was the mid-1980s before we introduced the Measles vaccine for the first time (National Immunisation Office, 2018) [3].

Measles IrelandFigure. 2: Graph showing the annual number of deaths in Ireland from Measles since official records began in 1864. Source for raw data since records began sourced from, “Annual Reports on Marriages, Births and Deaths in Ireland, from 1864 to 2000” An Phríomh-Oifig Staidrimh, Central Statistics Office CSO. Arrow indicates when Ireland first introduced a vaccine against the Measles.

Now, as the vaccine against Measles was introduced in Ireland at a time when hardly a child passed to adulthood without having the Measles growing up. And the mortality graph has almost flat-lined (Fig. 26), perhaps, we can begin to see how other regions would have seen a near-flat lining of deaths from Measles by the mid-1980s too if they had not have introduced a vaccine to prevent Measles earlier. It seems that if none of our respective regions had tried to stop this common and virtually benign infection of childhood, the deaths would have ceased entirely as we left the 20th Century behind.

One can imagine that Measles would have become much like Scarlet Fever (the slightly older plague of children that also became a benign infection of childhood and seemed to disappear entirely) and perhaps infections of Measles would have become increasingly rare as well and like Scarlet Fever that we never tried to eradicate using vaccination (recall that antibiotics against this bacterial disease only became widely available after it had seemingly become eradicated on its own), if it did ever return, it was only to make sure that the children got their much needed natural immunising boosters to protect them and their offspring for the future.

In other words, one has to ask: did we really need such an intervention for Measles, considering that Nature had obviously done such a great job on her own? Perhaps now you can see that full resolution of natural infectious contagions comes down to one thing: mass exposure to the real authentic pathogen (and the more exposure, the better), not mass lack of exposure, and nature will do the rest. However, our health officials thought otherwise. We thought we could do it better than Nature herself as clearly indicated in the following quote.

Vaccination Before the Measles-Mumps-Rubella Vaccine


“To those who ask me ‘Why do you wish to eradicate measles?’” wrote Alexander Langmuir, chief epidemiologist at the Centers for Disease Control and Prevention from 1949 to 1970, I reply with the same answer that Hillary used when asked why he wished to climb Mt. Everest. He said “Because it is there.” To this may be added, “… and it can be done.”…

Hendriks, J., & Blume, S. (2013)


In other words, we had this mass vaccination policy because we had the weapon of choice at the ready, and eradication of wild Measles was seemingly within our grasp.

The only problem was as indicated above, that, as you will see as we proceed, vaccine immunity came nowhere near the life-long and generational immunity/protection of naturally acquired Measles. As you will see as we continue, vaccine failures and waning turned out to be a big issue for Measles – just as it had with so many others including Jenner’s vaccine against Smallpox back in the day.

However, where our efforts may have been somewhat justified regarding Smallpox, as health officials were not in possession of the full facts regarding how tame this had actually become compared to generations previous, with Measles, we really could have known better.

Now reviewing all of this in retrospect, it would appear that we may have actually created more problems for ourselves in the long run and we may have been highly misguided in believing that we could conquer Nature in this way.

In order to assess this fully, we need to return to the pre-vaccine era in the light of the sheer numbers of children getting the Measles whilst growing up compared to the likelihood of dying or having disabilities from the infection.

Evidence of Number of Cases of Measles in the Pre-Vaccine Era

It is only really from the 1940s onwards that many of our industrialised nations started to make Measles a notifiable disease, that we begin to get a glimpse into the numbers of infections (at least the ones we have official records for) as seen in one account from England and Wales in the following:

Atlas of Epidemic Britain: A Twentieth-Century Picture

During the first three full years of notification, 1940-42, over 1.15 million cases of measles were reported.

With this new information to hand, William Butler could inform a meeting of the Royal Statistical Society that:

“In looking through the Annual Reports of a number of Medical Officers of Health for the year 1940, I was impressed by the small number of deaths recorded in proportion to the number of cases notified in the districts to which they related.”

Smallman-Raynor, M and Cliff, A (2012, 50)


We are talking about over a million cases of Measles within a fairly short timeframe, which wasn’t unusual back in these days and yet, as the statistician remarked, there were so relatively few deaths. This observation is supported by historical accounts of the massive amount of Measles cases – almost every child had the Measles whilst growing up across many of our now modernised nations with correspondingly decreasing number of deaths, where available, as plotted on our respective mortality graphs for this era right up to 1950s/1960s. This simply reminds us that having an infection does not correspond in any way to your chances of dying from the disease.

It would appear, as based upon more in-depth research by the present writer that it depends upon the era of the pathogen and how long it has been circulating amongst our populations. The longer our ancestors were exposed over the generations, the greater the generational immunity resulting in less and less death until a contagion finally stops plaguing us altogether.

Moving forward in time, we begin to fill out the picture of the pre-vaccine era regarding the actual ratio of expected deaths to notified cases (remember that many cases of Measles would have been so mild that they may not have been officially notified at all).

For instance, we have a more specific indication of the ratio of deaths to reported cases of Measles from around the 1950s as an average across our developed or industrialised nations of about 1 death in every 10.000 reported cases as indicated in the following excerpt which also compares this relatively low rate with the larger rate in less developed nations.

Measles deaths in the 1950s in industrialized countries

Whatever its toll in industrialized countries, where the measles fatality rate is 1 per 10,000 cases (Babbott and Gordon, 1954), measles has been a far greater scourge in developing countries, with case fatality rates as high as 1,000 per 10,000 cases (Morley, 1974).

Institute of Medicine (US)

(1994, Chapter 6, Measles and Mumps Vaccines)


The importance of the figures of deaths from Measles from less developed nations given above is that although a thousand deaths in every 10.000 reported cases of Measles, is that with this increasing immunity due to massive exposure, it is reasonable to suggest that it would not be long before they too would also experience similarly low fatality rates to the more industrialised nations – it would simply be a matter of time. But, alas, we may never know as mass vaccination swept across all of theses nations almost as virulently as the Measles virus.

Mass Vaccination Against Measles Some Years On

The great triumph that ushered in the mass vaccination starting in the United States, although, this led to a fairly remarkable coverage – but, their hopes were dashed as the virus proved rather difficult to control, even by having such a highly vaccinated school-aged population as seen in the following article excerpted next.

Measles Control in the United States: Problems of the Past and Challenges for the Future

…during the 1970s, all states passed laws mandating documentation of immunization against measles and other childhood diseases for entry into school. By the early 1980s, high immunization rates were achieved for school-age children; more than 95% of children were completely immunized by the time of school entry.

…Immunization efforts during the 1980s, however, failed to eradicate indigenous measles, and the number of reported cases averaged 3,700/year until 1989…

Wood, D.L & Brunell, P. A., (1995, 260)


Such outbreaks amongst highly vaccinated populations culminated in the United States in the most severe epidemic of the late 1980s, early 1990s as continued from the above article as outlined in the following:

Measles Control in the United States: Problems of the Past and Challenges for the Future

During the 1970s and 1980s, measles outbreaks in schoolage children accounted for the majority of reported measles cases… From 1985 to 1988 there were a median of 47 outbreaks among school-age populations and only 8 outbreaks among preschool populations…

In 1989, the number of outbreaks among school-age children swelled to 170 and the number of total reported measles cases increased to more than 18,000, with 41 deaths. The epidemic continued unabated through 1990, when 27,786 cases were reported, with more than 60 deaths…

In 1989, the majority of reported cases were in school-age or college-age individuals and a minority were in preschool children… Approximately 80% of the affected school-age children were appropriately vaccinated.

Studies have documented that epidemics of measles can be sustained in school-age populations despite their having very high vaccination rates.


Note the age shift of those infected by Measles in these post-vaccine era epidemic outbreaks has shifted from younger children (usually pre-school age); the age group who typically got the Measles infection naturally, to the older school-age and even college-age students who had grown up without immunity against the Measles. This shift in the older age group pattern of those most commonly now infected in the post-vaccine era is like history repeating itself (recall vaccine waning immunity and Smallpox).

It was the school children and college-age young adults group who were most commonly the source of the post-mandated vaccination epidemics of Measles who got infected themselves, who would not be the typical age group in which Measles would naturally erupt in the pre-vaccine era as most of them would already have had the infection as younger children and grown up with life-long immunity.

As you can see, this major epidemic within the United States was particularly tragic and hugely infuriating and massively disappointing for our well-intentioned public health officials as they slowly came to terms with the possibility that perhaps the slogan ‘Stop Measles with One Shot’ was becoming as irrelevant to parents as it was to the bugs themselves.

Now with these first-generation Measles outbreaks erupting within highly vaccinated populations, for the most part, one has to ask, did the long-term suppression of restricting the natural circulation of the wild Measles virus resulting in an entire generation of children who had grown up unexposed for the most part to the natural immunising of boosting effect of naturally circulating Measles, amplify the severity of such outbreaks?

Consider the following, where for instance, you can see below the case to death ratio – the actual deaths calculated from the numbers of reported infections of Measles, just a short generation after the introduction of mass vaccination against the Measles is remarkably high; 55,622 cases of Measles over the course of this epidemic (1989-1991) and a total of 123 deaths resulting in just over 2 deaths per 1000 cases as established by calculating the statistics recorded by the CDC Pinkbook tabulations from May 2019 [8].

No wonder it was this Measles epidemic more than most that had culminated in 1989 through to 1990 in the United States that urgently prompted the recommendation second dose MMR:

One has to ask, how come the risk of deaths/disabilities to cases of Measles in the 1950s in the same industrialised region was so much less (at 1 in 10,000 cases of Measles and decreasing thereafter) than getting it in the late 1980s/early 1990s?

Now, I also noticed that this is the very same risk ratio of 1 or 2 deaths per 1000 cases of Measles averaging out over the series of Measles outbreaks prior to and including the late 1980s – early 1990s epidemic in the United States and as documented statistically elsewhere in similarly severe post-mass vaccination Measles epidemics is the presumed risk ratio that many parents seeking medical advice regarding the case for vaccinating against Measles versus getting the wild version. This is truly not justified, as this high risk for catching the Measles of 1 or 2 in every 1000 doesn’t apply to natural Measles under normal circumstances.

I only mention it, as I feel we are being very disingenuous to nature herself, as after all, these figures are based upon a very unusually severe eruption after a long artificial suppression of the natural infections via vaccination – i.e., they are from outbreaks of Measles that first erupted within highly vaccinated populations in the first place due to the inadequacies of both long-term and rather poor protection in a sizable portion of the vaccinated population that the single-dose MMR offered as is now broadly acknowledged by most of our public health officials and infectious disease control experts.

Do also bear in mind, that this rather alarming estimated number of deaths to cases of Measles also contrasts with regions such as Ireland that didn’t see the Measles vaccine until the mid-1980s (a few years prior to this particularly severe post-mass vaccination eruption of Measles culminating in the late 1980s through to the early 1990s) were the case rate in Ireland was virtually zero deaths/disabilities to hundreds of thousands of cases as most children had the Measles growing up.

Seemingly, anywhere in the industrialised world that had relatively early and mass vaccination coverage experienced similarly severe epidemics a few decades after the implementation of the first MMR/Measles vaccine. Even Ireland experienced a relatively severe eruption in the early 2000s with a few infant casualties. But, thankfully nothing as serious has occurred since – even though we have seen outbreaks of wild Measles since. This brings us to another fall out of our respective mass vaccination coverage to attempt to eradicate Measles, which we will review in the next section.

Vaccinated Mothers can no longer protect their most vulnerable infants the way they used to in the Pre-Vaccine Era

Now we find when we dig deeper into the deaths that resulted from the major Measles outbreaks of the later 1980s and early 1990s in the United States as documented in the next excerpt (and seen elsewhere subsequent to our mass vaccination policies), that when we review the statistics, it turns out that it was the infants who became the greatest casualties in our war on the Measles bug, which itself prompted the call for infants and small children under one year old to be vaccinated earlier to help protect this most vulnerable group.

Measles Control in the United States: Problems of the Past and Challenges for the Future

… During the 1989 to 1991 epidemic, the attack rate for children under 1 year of age in urban communities reached 119/100,000, the highest of any age group…

In addition, the morbidity and mortality were highest among this age group. Therefore, a vaccine effective in preventing measles in infants less than 1 year of age is greatly needed worldwide …

Wood, D. L. & Brunell, P. A., (1995, 265)


In order to put this in context, we have to understand that this was unusual as in the pre-vaccine era, this is the age group that typically did not get the full-blown Measles as they were for the most part protected by their mother’s maternal antibodies (a type of attenuated or weakened version of the Measles virus that would familiarise the infant without causing an actual more life-threatening attack), Niewiesk, S., (2014) [10].

Maternal Antibodies: Clinical Significance, Mechanism of Interference with Immune Responses, and Possible Vaccination Strategies, that their mothers’ would have due to having the wild Measles infection herself whilst growing up when she was at an appropriate age to deal with it.

Essentially, infants were becoming increasingly the most vulnerable as they were too young to be vaccinated themselves as highlighted in accumulating studies, although the second dose MMR as prompted by the inadequate protection of the single dose, the infant population still remained the most vulnerable as we can see from the following more recent assessments of this situation.

Loss of Passively Acquired Maternal Antibodies in Highly Vaccinated Populations…

Measles outbreaks in countries with high measles vaccine coverage have demonstrated a shift in measles incidence to children <12 months of age …

As with previous studies, the authors note significantly lower measles antibody titers in infants born to women from the highly vaccinated populations in comparison to those born to mothers with presumed naturally induced immunity.

Gans, H. A. &. Maldonado, Y. A. (2013)


This is further echoed in the following studies dating again to our more modern vaccine era such as that highlighted in the following excerpt relating to our more recent experiences in the European Union, which is becoming a near-universal theme of late across all of our first world nations as seen in the growing number of science papers addressing similar issues.

New measles vaccination schedules in the European countries?

…Measles is a highly infectious disease …

Old studies on measles infection showed that infants were protected against measles with maternal antibodies over the first year of their lives. Vaccination of infants after 12 months of age aimed at avoiding the neutralizing effect of maternal antibodies and in turn improving measles vaccine effectiveness …

Based on the results of measles outbreaks, especially age of affected patients, we should consider changing measles vaccination schedules in all EU countries…

vaccinated mothers aged between 30 and 40 years old provide very low levels of antibodies to their infants, not sufficient to protect them over the first 12 months of their lives …[also] the prevalence of breast feeding is lowering or at least reduced in duration all over the EU countries… Maternal milk provides antibodies which offers major protection for infants against many bacterial and viral infections including measles …

…In conclusion, administrating the first dose of measles vaccine in the EU countries should be considered before 12 months of age, most probably at 9 months of age.

Allam M. F. (2014, Summary)


As indicated above, this issue of significantly lesser protective duration and quality of maternal antibodies from increasingly vaccinated populations of mothers has not gone away. Hence, we are beginning to grasp that there is a correspondingly greater need for earlier vaccination. The following example of another relatively recent paper dating to 2013 again addresses similar issues emerging within highly vaccinated populations within the Netherlands.

Waning of Maternal Antibodies Against Measles, Mumps, Rubella, and Varicella in Communities With Contrasting Vaccination Coverage

…Mothers who received MMR vaccine tend to have a lower concentration of measles virus–specific antibodies than mothers who naturally acquired measles…

Infants born to measles-vaccinated mothers are hence likely to have lower levels maternal antibodies at birth and a shorter period of protection than infants of mothers who acquired measles naturally …

In countries with high MMR vaccination coverage, such as the Netherlands, most women of childbearing age are vaccinated against measles and have avoided natural infection. …

Sandra Waaijenborg, S. et al. (2013)


The moral of this story is that we appear to have shot ourselves in the foot regarding mass vaccination as a means of protection against Measles. You see, Nature appears to have already found a means of protecting newborn infants right up to a year old and beyond in some cases via their mother’s own experience with the Measles and indeed, all other infectious type diseases that we have investigated in this way.

The only requirement is that she herself had exposure whilst growing up and it is this natural immunisation process, or becoming increasingly familiar with certain pathogens, that helped to ultimately resolve these vulnerabilities either well before a vaccine became available, or certainly on the cusp of a fuller resolution within our industrialised nations as we began introducing mass vaccination against such diseases.

But, all may not be as gloomy after all, as you will see as we further investigate our more current insights into the fall out of living in a world which has become heavily dependent upon vaccine protection against the Measles virus which is equally applicable to all the major and once deadlier infectious diseases that we now recommend as vaccine-preventable.

Are We Becoming Generationally Resilient to Dying from Measles Once Again?

Now it wasn’t long after we started giving the second MMR dose that a whole generation of highly vaccinated children grew to maturity with ever-decreasing protection against the Measles as is becoming abundantly clear, particularly in more recent years due to the significantly decreasing effect of natural boosting from the wild Measles circulation – one could argue, due to the success of high vaccination coverage across our first world populations.

It turns out, as you will see from the following studies investigating such issues, that even after being fully vaccinated as a child with at least two doses of MMR, your protection will seemingly wear off significantly by the time you reach adulthood and it is very likely that you would get the infection if you encountered it in an outbreak.

The next study is a case in point where it has recently specifically investigated this issue of the longevity of 2 dose MMR within highly vaccinated populations in Taiwan and demonstrated with statistical significance that these young adults would not be able to avoid getting the Measles in an outbreak and this has consequences for many other regions where high vaccination coverage and uptake rates have been maintained for a significant period of time.

Waning population immunity to measles in Taiwan

To evaluate the population immunity to measles in Taiwan where the coverage rate of the measles vaccine was >95% for more than a decade…

In subgroups aged 2-25 years, to whom at least 2 doses of measles-containing vaccine were given, there was a declining trend of seropositivity with age from 94.5% at 2 years to 50.6% at 21-25 years (p<0.0001)…

Seroprevalence was uniformly >95% in the older population (≥ 35 years) who had not been immunized against measles.

The waning vaccine-induced immunity may have impact on the control of measles in the future, especially when the vaccinated population becomes older.

Chen C. J. et al (2012, Abstract)


These findings are supported from around the world within increasing investigations demonstrating that the longer-term use of 2 doses of MMR doesn’t actually appear to have resolved the issues of vaccine waning over time since the date of last immunisation, leaving the young adult population the most vulnerable to getting the Measles and indeed other infections that the MMR is supposed to protect against as exemplified in the next study from Finland, particularly with the absence of natural boosting from the wild Measles virus.

The study also suggests that in the light of these findings that a third dose MMR should be considered. However, as you will see further on, studies that have investigated such are far from encouraging with regard to the length and strength of protection that this might offer.

MMR vaccination and disease elimination: The Finnish experience

An increasing part of the Finnish population is MMR-vaccinated. Over 95% of the population up to 35 years of age has been vaccinated twice…

A study on the immunity of the whole population against measles, mumps and rubella, carried out among different groups, showed that vaccinated age groups have antibody levels significantly lower than those of naturally infected individuals… These findings are in line with the results of antibody-persistence studies, which confirm that in the absence of natural boosters, a decline in vaccine-induced antibodies takes place…

The MMR vaccine was believed to induce life-long immunity against measles, mumps and rubella, although that has not proved to be true … Our antibody follow-up studies among the vaccinated cohort strongly suggest that immunity wanes…

On the basis of the decline in antibodies observed after the administration of two doses of the MMR vaccine, a third dose may be needed at the time of young adulthood…

Davidkin, I., et al (2010)


Now, as the excerpted investigations above within highly vaccinated populations suggest, in the face of an outbreak, it would be unlikely that even full vaccination compliance would hold up and this is borne out in the following outbreaks of Measles that are presented throughout the rest of this section.

Fortunately, however, the characteristics of much more recent outbreaks commonly now impacting highly vaccinated populations due to vaccine failures have turned out to be rather tame; certainly, when we compare such Measles outbreaks across our first-world nations with the second generation post-vaccination era eruptions discussed previously, deaths and injuries from such recent outbreaks are notable by their absence from all of the reports investigated here.

All in all, as you will see from the samples of fairly recent Measles eruptions presented here, it looks like we may becoming quite resilient to the Measles virus once again and we may in part, have to thank our vaccination failures for this most welcomed return to more robust immunity.

Take for example the outbreak of Measles in Korea mostly impacting children less than one year old (and therefore, too young to be vaccinated) and yet, this population appear to have survived rather well as no deaths or disabilities were reported as a result. Furthermore, the other age group most impacted in the Measles outbreaks were adolescents and young adults whose vaccination protection against the Measles (two-dose MMR) given in childhood had seemingly worn off (waned) are not reported as having suffered greatly due to the outbreaks.

Essentially, it looks like all of the cases not only survived unscathed but, ended up with life-long immunity to the Measles as a result. Could vaccine waning immunity by providing a strange means of natural boosting and building up an ever-increasing population dependent upon real exposure for full, robust and generational protection?

An increasing, potentially measles-susceptible population over time after vaccination in Korea

Waning levels of measles antibodies with increasing time post-vaccination suggests that measles susceptibility is potentially increasing in Korea. This trend may be related to limitations of vaccine-induced immunity in the absence of natural boosting by the wild virus, compared to naturally acquired immunity triggered by measles infection. This study provides an important view into the current measles herd immunity in Korea…

In Korea, the measles-containing vaccine (MCV) became available in 1965, and the trivalent measles, mumps, and rubella (MMR) vaccine was introduced in early 1980s. A 2-dose MMR vaccination schedule was recommended beginning in 1997, with the first dose given at 12–15 months of age and the second dose given at 4–6 years of age…

Although measles had been eliminated in Korea, the resurgence of measles outbreaks related to imported and import-associated measles cases occurred during 2013–2014. Most patients with measles were infants aged <1 year, but measles cases were also identified in patients aged 13–24 old who had received a 2-dose measles vaccination…

Measles outbreaks among highly vaccinated populations have been observed in many countries…

… Our data showed good agreement between the incidence of measles and the susceptible age groups (adolescents and young adults) with measles seronegativity observed, suggesting the potential accumulation of measles-susceptible individuals in the population due to waning immunity, which may pose increased risk for measles outbreaks following measles importation from other endemic countries.

Kang, H. J. et al (2017, Conclusions)


The tameness of such recently emerging Measles outbreaks impacting highly vaccinated populations in particular (and thankfully not negatively impacting infants too young to be vaccinated to any concerning extent within first-world nations) may be accounted for by the fact that the type of Measles encountered most frequently is often described as fairly mild and even without obvious symptoms and has come to be known as modified Measles which are most common amongst highly vaccinated young people whose vaccination since childhood have waned. These outbreaks are also often described as self-limiting and another recent example is given in the following from Israel.

Measles Outbreak in a Highly Vaccinated Population — Israel, July–August 2017

On August 6, 2017, the Israeli Defense Force Public Heath Branch (IDFPHB) was notified of two suspected measles cases. IDFPHB conducted an epidemiologic investigation, which identified nine measles cases in a population with high measles vaccination coverage.

All measles patients had signs and symptoms consistent with modified measles (i.e., less severe disease with milder rash, fever, or both, with or without other mild typical measles symptoms). A total of 1,392 contacts were identified, and 162 received postexposure prophylaxis (PEP) with measles-mumps-rubella (MMR) vaccine; the remaining contacts were followed for 21 days (one incubation period). No tertiary cases were identified.

Avramovich E, et al (2017, Abstract)


Another case in point of both an outbreak of Measles impacting highly vaccinated young people in particular who presented with the mild form (Modified Measles for the most part) and an outbreak that was self-limiting is outlined in the following recent cases of Measles in Taiwan.

Occurrence of modified measles during outbreak in Taiwan in 2018

To the editor: We read with great interest the rapid communication by Mizumoto et al … regarding modified measles in Japan, 2018. In particular, we discovered that the index case in Japan was epidemiologically linked to an outbreak in Taiwan […]; measles was transmitted on board an aircraft while the case returned to Taiwan from Thailand, before travelling on to Japan while febrile and contagious.

Measles was confirmed in three members of the cabin crew and one passenger that shared the same aircraft as the index case. Further transmission by the infected cabin crew members occurred and involved an additional seven staff. One passenger that contracted measles in the airport caused a secondary cluster of four cases with ca 1,000 contacts in Chang Gung Memorial Hospital, Taiwan…

In 2018, during the outbreak in Taiwan, from March to April involving 24 cases.., we found that in the aircraft cluster 12 of 13 measles cases were young adults aged 20–40 years who had been immunised with two doses of measles-containing vaccine during childhood…

The presentation of measles was modified in these cases, making the clinical suspicion of measles very difficult; in the serological tests… In cases presenting with modified measles transmission was limited, as further infections occurred in only three cases among 1,000 contacts in the hospital cluster and these cases had close and long-time contact with the modified measles cases.

Although the uptake of two-dose measles vaccine in children was maintained at > 95% for 40 years in Taiwan, the measles outbreak in younger age groups was not unexpected. We have shown that vaccine-induced humoral immunity to measles can wane to a very low level (50–60%) in young adults…

The measles outbreak in Taiwan seems to have mainly resulted from secondary vaccine failure rather than suboptimal vaccination coverage.

Chen, C-J., Lin, T-Y., & Huang, Y-C. (2018)


The spread of Measles was remarkably self-limiting, even the wild type with more obvious symptoms, and rather self-limiting also within the confined space of the aircraft where only a handful of fully-vaccinated young adults were infected, even if they did manage to pass it on to some hospital staff who were in close quarters with them.

And as also noted above, this outbreak in the younger age group – fully vaccinated with two doses of MMR, was not unexpected, as the authors had previously demonstrated (secondary vaccine failure).

This next case, again relating to Japan, is also of interest because although it had quite a sizable proportion of infected individuals who presented with more typical Measles symptoms and were unvaccinated (although more than half were fully vaccinated in this outbreak and tended to spread the infection less and had the milder and less obvious form of the Measles infection), it is really surprising how little the outbreak spread amongst the populations in general, particularly, considering the many opportunities for the virus to do so.

The following account also points out, there was a strong association between the number of MMR doses that those infected had received and the mildness of having the Measles.

The Largest Measles Outbreak, Including 38 Modified Measles and 22 Typical Measles Cases in Its Elimination Era in Yamagata, Japan, 2017

The incidence of modified measles (M-Me), characterized by milder symptoms than those of typical measles (T-Me), has been increasing in Japan. However, the outbreak dominated by M-Me cases has not been thoroughly investigated worldwide. .. This phenomenon was observed after Japan had achieved measles elimination in 2015.

We confirmed 60 cases by detecting the genome of the measles virus (MeV). Among the cases, 38 were M-Me and 22 were T-Me. Thirty-nine (65.0%) patients were 20–39 years of age. Three out of 7 primary cases produced 50 transmissions, of which each patient caused 9–25 transmissions. These patients were 22–31 years old and were not vaccinated.

Moreover, they developed T-Me and kept contact with the public during their symptomatic periods. Considering that M-Me is generally caused by vaccine failure, some individuals in Japan may have insufficient immunity for MeV. Accordingly, additional doses of measles vaccine may be necessary in preventing measles importation and endemicity among individuals aged 20–39 years…

… Outbreak description: During the outbreak, 60 measles cases were confirmed from March 3 to April 15, 2017… The index case involved a man in his twenties who had traveled to Bali Island, Indonesia, from February 20 to February 26, 2017… After the index case, 25 second-generation cases, 27 third-generation cases, 2 fourth-generation cases, and 5 cases of unknown origin were reported…

On May 17, 2017, measles epidemic had ended because no additional cases were observed for 4 weeks… Approximately 65.0% of the patients were 20–39 years. Among the 36 vaccinated patients, 83.3% presented with M-Me… Asymptotic linear-by-linear association test indicated a trend in which the proportion of M-Me cases increased with increasing vaccination doses…

Transmission pathways: We confirmed that 54 of 59 cases had a direct or indirect epidemiological association with the index case… In conclusion, the measles outbreak in Yamagata Prefecture, Japan, in 2017 was caused by importation and was transmitted primarily by 3 unvaccinated patients… including the index case.

Komabayashi, K. et al (2018, Summary)


These infections of Measles would presumably produce life-long immunity, not just for those who were not vaccinated even if they tended to be more infectious and spread the virus more than their vaccinated counterparts, but, those with vaccine waning immunity would also have become immune for life – even if the symptoms are expressed in a more mild form due to having at least some familiarity with the pathogen as a result of their vaccination history.

You see many people are not actually aware that they have the Measles when exposed unwittingly to infection. We can see this particularly within highly vaccinated situations such as hospitals as exemplified in the following reports amongst health workers and patients, starting with a recent outbreak in Portugal:

Challenging measles case definition: three measles outbreaks in three Health Regions of Portugal

We report three simultaneous measles outbreaks with 112 confirmed cases in three Health Regions of Portugal, from February to April 2018. The mean age of cases was 30 years, 79% worked in a healthcare setting and 87% were vaccinated… Several cases presented with modified measles, highlighting the importance of rethinking the measles case definition for vaccinated cases.

We present preliminary findings and implemented control measures of three simultaneous measles outbreaks that occurred in Portugal between February and April 2018. One of the outbreaks took place in a hospital and represented a particular challenge for epidemiological and laboratory investigations as a substantial number of vaccinated healthcare workers (HCWs) developed benign clinical signs and symptoms of measles. We discuss these findings and highlight the need to expand the European Union (EU) measles case definition, in order to increase sensitivity in case capture among vaccinated individuals with modified measles and who do not meet the current European Union (EU) case definition…

Since the measles vaccine was introduced in the Portuguese National Immunisation Programme in 1974, the country has achieved a consistent and sustained high immunisation coverage against measles (> 95%) [11,14]. HCWs are at higher risk of measles exposure because the high intensity of the exposure and subsequent transmission to vulnerable patients… According to the National Measles Elimination Programme, HCWs are recommended to receive two doses of measles vaccine (either single measles-containing vaccine or MMR) or to have evidence of previous measles infection… However, measles outbreaks in healthcare settings are becoming more frequent in the European Region…

Countries, such as Portugal, which maintained a high vaccination coverage for many years and had eliminated measles, are at greater risk of modified measles cases emerging during outbreaks… Modified measles mainly affect young adults who were adequately vaccinated but with the last dose of the vaccine administered more than 10 years prior.

In one chain of transmission, a hospital cluster was identified and most cases were HCWs vaccinated with two or more doses of MMR vaccine. This was described in other outbreaks… and may be related to waning of vaccine-induced immunity in the absence of natural boosting by the wildtype virus…

The outbreaks described here, which included a number of cases with modified measles and a large number of cases among vaccinated HCWs, highlight the need for further investigation in order to recommend innovative approaches in future outbreaks: Nearly half of these cases would not have been identified using the current EU case definition.

Augusto, G. F., et al (2018, Abstract)


Another outbreak in a hospital situation has recently been reported in the Netherlands, again, amongst fully vaccinated health workers with very little spread and the typical presentation of modified and milder Measles as documented below.

Measles Outbreak Among Previously Immunized Healthcare Workers, the Netherlands, 2014

We investigated a measles outbreak among healthcare workers (HCWs) by assessing laboratory characteristics, measles vaccine effectiveness, and serological correlates for protection…

Cases were laboratory-confirmed measles in HCWs from hospital X during weeks 12–20 of 2014…

Eight HCWs were notified as measles cases; 6 were vaccinated with measles vaccine twice, 1 was vaccinated once, and 1 was unvaccinated… Among 106 potentially exposed HCWs, the estimated effectiveness of 2 doses of measles vaccine was 52%…

Measles occurred in 6 twice-vaccinated HCWs, despite 2 having adequate pre-exposure neutralizing antibodies. None of the twice-vaccinated cases had severe measles, and none had onward transmission, consistent with laboratory findings suggesting a secondary immune response…

Results of long-term follow-up studies of measles virus immunity among twice-vaccinated cohorts who have not been exposed to wild-type measles virus show considerable waning of immunity, raising the question whether a booster MMR vaccination is necessary…

Recent results by Fiebelkorn et al, however, suggest that administering a third dose of MMR to twice-vaccinated individuals has a limited long-term effect on the height and quality of the immune status… Larger studies to further explore the effects of MMR-3 are urgently needed.

… Enhanced surveillance and detailed laboratory characterization of measles vaccine failures will be crucial to establish the long-term effectiveness of measles vaccination programs.

Hahné, S. J. M. et al (2016)


However, as noted above, a third dose MMR may not be the solution to the waning vaccine immunity crisis as apparently, due to a more recent study indicates that this may not be that effective or particularly long-lasting either. Perhaps, given the increasing mildness of such outbreaks, to the point where we are finding it increasingly difficult to even spot the outbreaks these days, we should not worry so much.

Take, for example, the two physicians who contracted Measles without knowing it and because they were fully vaccinated they never thought for one minute they had the Measles and then, they went on to expose their patients, but everyone was fine, including unvaccinated individuals and at least now, these doctors won’t have to worry about having to keep getting vaccinated or, passing their infection on to their patients.

Two Case Studies of Modified Measles in Vaccinated Physicians Exposed to Primary Measles Cases: High Risk of Infection But Low Risk of Transmission

In 2009, measles outbreaks in Pennsylvania and Virginia resulted in the exposure and apparent infection of 2 physicians, both of whom had a documented history of vaccination with >2 doses of measles-mumps-rubella vaccine. These physicians were suspected of having been infected with measles after treating patients who subsequently received a diagnosis of measles.

The clinical presentation was nonclassical in regard to progression, duration, and severity. It is hypothesized that the 2 physicians mounted vigorous secondary immune responses typified by high avidity measles immunoglobulin G antibody and remarkably high neutralizing titers in response to intense and prolonged exposure to a primary measles case patient. Both of the physicians continued to see patients, because neither considered that they could have measles. Despite surveillance for cases among contacts, including unvaccinated persons, no additional cases were identified.

Rota, J. et al (2011, Abstract).


Where does all this leave herd immunity? After all, we are so often told that if only we could achieve at least 95 per cent vaccination uptake, there would be no Measles outbreaks and everyone, including those who cannot be vaccinated, would be protected.

However, in a strange sort of way we may be witnessing a means of bringing about more solid and robust community immunity back to pre-vaccine era levels (certainly to levels seen in Ireland before we introduced the vaccine against Measles), but, in a sort of ironic twist in all of this – we may already have greater community immunity than we realise, due in large part to vaccine failure, and we so firmly believed and hoped that One-Shot Would Be For Life, never mind, three or four and still counting.

All in all, secondary Measles vaccine failure is now recognised as more common than previously thought as more and more of our populations are growing up fully dependent upon vaccine-derived protection and not being boosted by naturally much these days, unless an outbreak occurs and then, they might end up with a modified form ultimately leading to lifelong immunity in the long run.

Now, as Jenner’s vaccine protection against Smallpox waned significantly within a fairly short period, this ironically may have allowed the natural pathogen to fully resolve itself by more natural means in the end. Therefore, for much of its history, and despite our best efforts, almost nobody grew to maturity without having the Pox in the end and ultimately became immune to dying as a result of having the infection whilst growing up, or as their vaccines wore off.

Well, it now looks like the story of our remarkable resistance to dying from the Measles may be due to maternal protective antibodies becoming increasingly attenuated (weakened) and a much less virulent virus as each generation is exposed is somewhat similar – only its story began a little later in history than Smallpox and, because of this, we are making its particular history as we speak.

Therefore, although we do not have the full picture as yet, it is hoped that nature will fully resolve the whole thing, despite our best efforts to eradicate this virus by more artificial means, in the end.


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