main article image
(Jacek Dylag/Unsplash)

Do You Still Need to Get Vaccinated if There's Herd Immunity? An Expert Explains

MICHAEL MINA, METAFACT
24 MAR 2019

18 verified experts answered this question on independent fact-checking platform Metafact.io. All answered 'near certain' or 'likely', this is one of them.

Absolutely. Most modern healthcare requires intense focus on the individual. As such most modern healthcare related medicines across a huge range (i.e. tylenol, chemotherapy, insulin, etc) are aimed at protecting and benefitting the individual and, for the most part, the effects of those medicines occur within the person who is taking them.

 

Vaccines are one of the very few items in modern healthcare where the beneficial effect has consider not only the individual receiving the vaccine, but also the population, and the population level choices.

Today, the chances of an individual child contracting measles are exceptionally low - BECAUSE vaccines have been so spectacularly effective at eliminating the disease from entire countries and even continents.

Towards the question at hand, if 92 percent of the population is vaccinated, those 92 percent of individuals will be an effective firewall, preventing the infection from spreading and causing disease in the 8 percent who are not vaccinated.

However, if an individual decides that he/she, or their child is protected because of the 'firewall' and therefore has such a low chance of getting the infection that they decide not to bother getting the vaccine, then they do not contribute to the firewall, creating a small crack in it.

At a population level, it is likely that their decision was either informed by or will inform other people's decisions to not vaccinate for the same reason.

 

And very quickly, the firewall will contain many cracks because many people think that there is no need.

In the case of measles, measles is so infectious that it only requires a few cracks to start a new measles outbreak. In more concrete numbers, as soon as the population that is vaccinated falls below about 94 percent, measles will began to come back.

We have seen this throughout Europe in 2017 and 2018, where hundreds of thousands of people have been infected with measles, and in the US as well, where small pockets of unvaccinated people led to numerous small cracks in the firewall, and thus an outbreak of measles occurred.

Therefore, unlike other modern medicines, vaccines have to be considered within the context of the larger population.

92 percent is already below what is considered a protective population level to keep herd immunity from breaking down. A further reduction in vaccination rates due to individual decisions to not vaccinate will degrade the firewall for everyone, and measles will return.

So yes, even if 92 percent of the population is vaccinated, it is absolutely beneficial to yourself to get vaccinated, as you help keep the firewall separating yourself and the infections standing up tall.

This expert response was published in partnership with independent fact-checking platform Metafact.io. Read all responses to the question here.

You can find out more about Metafact's mission to stop fake news and support it on Kickstarter.