In this year’s U.S. measles outbreak, parts of Brooklyn and Rockland County have experienced two-thirds of the reported 704 infections. The media generally blame an alleged low vaccination rate in these areas, each with a large percentage of ultra-Orthodox Jews.
Public health experts corroborate this message. Dr. Nancy Messonnier of the Centers for Disease Control testified to Congress: “I do believe that…most cases that we’re seeing are in unvaccinated communities.” Dr. Anthony Fauci, who heads the National Institute of Allergy and Infectious Diseases, declared:
“Coverage in a given community, when it falls below a certain critical level, you get the kinds of outbreaks that we’re seeing, particularly in places like New York City and the Williamsburg section of Brooklyn…. his is a relatively closed community, a Hasidic Jewish community in that area - that are not vaccinating their children at a rate that would provide that broad umbrella of protection that we call herd immunity…When you drop down to the 80s or even the 70s [emphasis added] or even lower, where it is now in that community, that’s exactly the explanation of why we’re seeing the outbreaks that we’re seeing.”
However, the New York State Health Department reports the average vaccination rate for measles among the nearly 200 Jewish K-12 schools in Brooklyn — mainly in Borough Park and Williamsburg — is 96%, six percentage points higher than the statewide average among private schools. In contrast, six other New York counties have a vaccination rate below 50%.
Moreover, the measles vaccination rate among Jewish school-age children is above the assumed 95% threshold required for “herd immunity,” i.e., protection of the community from sustained outbreaks.
What, then, explains the outbreak?
Regardless of the vaccination rate, some communities have characteristics that enhance and sustain epidemics. Population density and a community’s social mixing patterns are two critical determinants of whether an outbreak dies out or remains sustained. Orthodox Jewish communities are densely populated. Families have many children and interact frequently.
The vaccination rate of 95%, assumed to provide herd immunity, is derived from a basic model assuming the vaccine is effective 97% of the time, and that, in the absence of immunity an average infected individual transmits the infection to 12 others, the “basic reproduction number” (what we in medicine refer to as “R0”).
If, however, in a densely populated and highly interactive community, the average infected individual transmits measles to 24 others, then 99% of the community must be vaccinated in order to ensure herd immunity. If the average is 36, then even a 100% vaccination rate fails to ensure herd immunity. R0 estimates in the literature vary from 1 to 203.
Implicit in the current media coverage is the assumption that measles outbreaks should not occur anymore. But despite the fact that measles were declared eliminated from the United States in 2000, complete elimination may no longer be realistic.
Anyone born before 1957 is generally assumed to have complete natural immunity to measles, gained through childhood exposure to the virus. Today most rely on vaccination for their immunity, which is only 97% effective. Indeed, 13% of the typed 2019 cases were vaccinated.
Another obstacle to elimination is the persistence of “anti-vaxers” (though no evidence suggests that their presence among Orthodox Jews is above average). As long as there is a cohort of people refusing vaccination, together with a group which the vaccine fails to immunize, it will be extremely difficult to eliminate measles.
What remedies are available, then?
First, it is time to stop vilifying the Orthodox Jewish community when the data show their vaccination rates are as high as any. Continuing to blame this segment of the Jewish community — especially in the news media — is not only wrong. It actually jeopardizes the cooperation that is necessary to stem the outbreak.
Current recommendations are likely being revisited. In 1968, a single vaccine was believed to achieve lifelong immunity. However, from 1987 to 1992, a large outbreak infected many vaccinated young adults. The recommendation was then changed to administer two vaccine doses — the first at age one, and a second dose between the ages of 4 and 6. Upon review, the guidelines could perhaps change to recommend giving the second vaccine earlier, or even to administer a third dose.
Reducing measles here in the U.S. also calls for better international cooperation. From 2001 to 2016, 553 measles cases in the U.S. originated abroad. As of April 24 of this year, 170 countries have reported 112,163 measles cases to the World Health Organization — four times last year’s numbers. The trend calls for WHO to initiate a global vaccination campaign, similar to its successful campaign to eradicate the polio virus globally. This will, however, require large donations by first world governments and organizations like GAVI and the Gates Foundation.
Additionally, with the community’s cooperation and trust, the "identify, isolate and track” strategy, effective in containing the Ebola virus, could be implemented successfully.
Last but not least, anti-vaxers must be engaged respectfully instead of with derision or condescension. Some anti-vaxers’ concerns are, prima facie, reasonable. Their claim that vaccines are associated with autism is not. The only study ever claiming a relationship was fraudulent. And a new Annals of Internal Medicine study, once again, dispels any links.
Medical practitioners, especially, have a duty to provide clear explanations and to engage patients in joint decisionmaking. On the other hand, anti-vaxers must understand that their personal decision impacts others very significantly. We urge them to get vaccinated for the general good, as only very high vaccination rates prevent enduring outbreaks.
In summary, there is a worldwide and national surge in measles, disproportionately affecting the Orthodox Jewish community, even though its vaccination rate is similar to those elsewhere. Outbreaks are more likely in dense populations with frequent social mixing patterns. Blaming the Jewish community is therefore wrong, offensive and counterproductive by enhancing resistance and suspicion.
Vaccination rates should be maximized, nationally and globally, and the current vaccination schedule reevaluated. Finally, antivaxers should reevaluate the relative risks, understand that autism is a baseless concern, and consider the benefit vaccination provides to society.