The recent outbreak of mumps at Harvard University was due to the fact that vaccinated students spread the disease throughout the campus, according to the Public Health department.
Researchers are now saying that any new outbreaks of mumps are likely to originate from people who are vaccinated against the disease, and not from those who remain unvaccinated.
Four other campuses in Boston are also starting to see cases, as have four universities in Indiana. About 13 cases of mumps have also cropped up in California.
One ridiculous explanation offered by Dr. Amesh Adalja, an infectious-disease specialist at the University of Pittsburgh Medical Center’s Center for Health Security, is that the vaccine only works if the exposure to the virus is low; it can’t be expected to work if there are high amounts of exposure, such as in dorms:
“The exposure that they have to mumps is so high in these situations that it overcomes the ability of the vaccine to protect them,” Adalja told Live Science. “It may be that, in these special situations, a much higher level of antibodies [against mumps] is needed to keep the virus at bay.”
In 2009, more than 1,000 people in New Jersey and New York contracted the disease. At the time, questions arose about the effectiveness of the vaccine because 77 percent of those sickened were vaccinated.
A similar scenario occurred in 2006, when mumps infected more than 6,500 people in the U.S. Most of those cases also occurred among the vaccinated population, primarily among college students who had received two doses of MMR vaccine.
Now, if a vaccine is indeed highly effective, and avoiding the disease in question is worth the risk of the potential side effects from the vaccine, then many people would conclude that the vaccine’s benefits outweigh the risks.
However, if the vaccine is ineffective, and/or if the disease doesn’t pose a great threat to begin with, then the vaccine may indeed pose an unacceptable risk. This is particularly true if the vaccine has been linked to serious side effects.
Unfortunately, that’s the case with the MMR vaccine, which has been linked to at least 98 deaths and 694 disabilities between 2003 and 2015. Considering the fact that only 1 to 10 percent of vaccine reactions are ever reported, those numbers could actually be closer to 980 deaths and 6,940 disabilities.
Meanwhile, death from mumps is “exceedingly rare” according to the CDC, and no one has died from mumps during any of the recent outbreaks.