What is the issue with measles? The issue is that measles has not disappeared and in most parts of the world it accounts for many of the deaths of children- in India it is still one of the leading infectious disease causes of childhood deaths. Here in the U.S., we have become complacent about this vaccine preventable disease, and in the anti-vaccination community, more so. In the past, we have placed our faith upon the “herd immunity” concept in protecting us from communicable diseases. Herd immunity relies on the assumption that if a significant number of members of the community (or herd) have resistance to a disease (and that percentage varies according to the disease) then someone who doesn’t is protected by that “ring of immunity” around them (provided by the “herd”). So, if someone isn’t vaccinated, there is a strong likelihood they will have some degree of protection, since the disease they are at risk for won’t be circulating through the herd.
Well, in the age of rapid, world-wide travel – where the next pandemic could be an airline flight away- this just doesn’t hold true anymore. The percentage of a population needed to confer “herd immunity” for measles has been estimated at between 93-95%. This also assumes that things are stable within the herd. When we are dealing with a disease that is highly communicable (it has been estimated that one person with measles can infect 18 others!) it just doesn’t work in the age of world travel. If a person with no immunity goes to a country where there is a disease that is prevalent, or is there during an outbreak, then that person will contract the disease and/or bring it back to his/her community. If the immunity of the community, or the population that person circulates in, is less than 95% (this is the figure for measles protection), then there will be an outbreak. This is just what we have seen in the present outbreak in Brooklyn, where over 200 cases have occurred. Israel, (where, as I understand, there were recent visits by members of the affected Brooklyn community) has just gotten over an epidemic of measles (~3400) cases. According to the WHO, most were thought to have been brought in by tourists who were not immunized against the disease.
So let’s take a quick look around the world: in the WHO Western Pacific Region in 2018 there were over 26,000 cases where the Philippines and China “led the pack”; in the WHO South and East Asian Region there were over 75,000 cases in 2018 where India clearly “led the pack” followed by Bangladesh; in the Americas in 2018, there were ~16,000 confirmed cases with Venezuela and Brazil “leading the pack”; and in the Who European region there were ~80,000 cases in 2018 with the Ukraine accounting for well over 30,000 of these. So, we are dealing with a disease that has not been eradicated, is highly contagious and, where in many parts of our own country, immunization rates among children have fallen below the required threshold to prevent its spread.
Clearly, there is no surprise that we are in the midst of a measles outbreak in the U.S.- 314 cases in 15 different states, to date. This statistic is both depressing and appalling, because measles is so preventable; after one dose of MMR vaccine the efficacy is close to 93% and after the second dose it’s closer to 97%! We forget that measles is not without complications- 1 in 10 children will develop a severe ear infection because of measles; 1 in 20 people will develop a pneumonia; 1-2/1000 may die and 1/1000 may develop an encephalitis. So tragic, and so preventable.