Questão 15 - IDOMED Medicina 2024/2

RE-EMERGING DISEASES

 

By Robyn Correll, MPH

 

    In the past century or so, humans have fought, and won, their fair share of battles with diseases. Vaccines defeated smallpox, antibiotics conquered Scarlet Fever, and insecticide scaled back mosquito-borne illnesses. Despite these successes, some diseases appear to be making a comeback. Outbreaks of measles and mumps have made more than a few headlines of late, for example.

    One of the greatest public health achievements in history, vaccines are credited for the massive decline of potentially dangerous diseases like measles and polio. But, although the majority of families embrace vaccination, a growing number appear to be delaying or forgoing vaccines altogether, due to a misunderstanding of the safety, effectiveness, and necessity of vaccination.

    In Texas, for example, the number of students with nonmedical exemptions to school vaccine requirements has skyrocketed from just 10,404 in 2007 to 52,756 in 2017. While the overall vaccination rate for measles in Texas held fairly steady between 2007 and 2017, with a rate of about 97% for students, research shows that unvaccinated individuals tend to cluster in the same communities and schools. This results in a breakdown of protective herd immunity, leaving those individuals vulnerable to outbreaks of disease.

    According to a review published in JAMA, high numbers of vaccine refusers in a given community increase the risk of measles not just for unvaccinated individuals, but for vaccinated people too. That’s because no vaccine is 100% effective. Some people who receive the vaccine might not respond to it and could get sick anyway if they are exposed to the virus. And many of the individuals involved in recent outbreaks of mumps and pertussis have been at least partially vaccinated. Does that mean that the vaccine doesn’t work?

    Pertussis vaccines are about 80% to 90% effective when they’re first given. Mumps vaccines are about 88% effective after two doses. As time goes on, however, research suggests that immunity wanes, and more doses might be needed to protect against outbreaks.

    Additionally, while some of these pathogens are, indeed, showing signs of a resurgence, many more are conquered every day through large-scale and coordinated public health efforts and the significance of this success shouldn’t be overlooked.

Adapted from: https://www.verywellhealth.com/why-some-diseases-are-re-emerging-4151072 Accessed 5 February 2022

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