A study published last year in the New England Journal of Medicine took a closer look at the mumps outbreak that occurred in New York and New Jersey from June 28, 2009, through June 27, 2010. A total of 3502 outbreak-related cases of mumps were reported and of the 1648 cases for which clinical specimens were available the following data was comprised:
- Orthodox Jewish persons accounted for 97 percent of case patients.
- 27 percent of all patients were adolescents 13 to 17 years of age.
- Males (78 percent of patients in that age group) were disproportionately affected.
- Among those affected 13 to 17 years of age, 89 percent had previously received two doses of a mumps-containing vaccine, and eight percent had received one dose.
- Transmission was focused within Jewish schools for boys, where students spend many hours daily in intense, face-to-face interaction.
- It is suspected by the researchers that, because the mumps outbreak did not spread to surrounding communities, effectiveness of the two-dose MMR vaccine schedule in validated.
The researchers from this study concluded that, “The epidemiologic features of this outbreak suggest that intense exposures, particularly among boys in schools, facilitated transmission and overcame vaccine-induced protection in these patients.” They also suggest that the “vaccination appeared to limit the severity of cases; complication rates were lower than rates reported during the prevaccine era.”
The Mumps Vaccine
Since 1967, a mumps-virus vaccine has been available in the United States. Ten years later, a single dose was recommended for children 12 months of age or older. In 1989, a second dose of measles-mumps-rubella (MMR) vaccine became standard for children 4 to 6 years of age.
Single-dose MMR vaccine coverage among children 19 to 35 months of age during the period from 1995 through 2010 ranged from 90 percent to 93 percent, and two-dose MMR vaccine coverage among adolescents 13 to 17 years of age during the period from 2006 through 2010 ranged from 87 percent to 91 percent. It is reported that by 2005, the incidence of mumps in the United States had fallen by more than 99 percent from the incidence in the prevaccine era.
It is of interest to note that during 2006, an American outbreak of mumps occurred in college-age persons in which the two-dose mumps vaccination coverage was 79 percent to 99 percent. During subsequent years, outbreaks were reported in other countries in populations with high two-dose coverage.
Key Take-Aways
- The primary take-away about these statistics is that these mumps outbreaks occurred in people who were fully vaccinated against mumps. This fact alone begs the question, “How effective is the mumps vaccine?”
- The second take-away is that there are no reported deaths from these outbreaks which begs the question, “Why do we even vaccinate for mumps?
- Third, it has become clear that the risk of infection with mumps may be higher when the exposure dose of virus is large or intensely transmitted. This phenomenon can also explain why the efficacy of the mumps vaccine tends to be lower among household contacts than among school or community contacts.
- Lastly, these outbreaks and research studies tell one thing that is very clear: Vaccines are not infallible. Instead of just blindly following the advice of yesteryear, more (honest) research is needed by open-minded scientists to get to the bottom of the issue.
The BIG Question
Possibly the most challenging decision new parents have to make is whether or not to vaccinate their newborns. The vaccine-autism issue is hotly debated by both sides and everyone seems to have the “latest evidence” proving their perspective. Quite honestly, it’s a very confusing issue.
Subsequently, there great inconsistency within the medical system and no “standard of care” is being following on the issue. On the one hand, many pediatricians adamantly push vaccines on their patient(s). On the other, an ever-growing group of physicians are becoming more “hands-off” and leave the matter open to the parents to decide.
When making your own decision about whether to vaccinate your child or whether to receive one for yourself, look at the whole picture. Consider the research being published by both sides and go to pro-vaccine and anti-vaccine websites to get the full effect. You may be surprised where you’ll end up on the issue.
Sources for this article include:
- www.nejm.org/doi/full/10.1056/NEJMoa1202865#t=articleTop
