Chompoo Suriyo/Shutterstock

It's Official: Anti-Vaxxers Most Likely to Blame For Rise in Measles

ಠ_ಠ

MICHELLE STARR
4 OCT 2017
 

There is a growing body of evidence that failing to vaccinate children is actively harmful. And according to the most recent study, an increasing number of measles outbreaks is linked to people leaving themselves or their children unvaccinated against the viral infection.

 

A team of researchers studied 1,789 cases of measles in the US between 2001 and 2015, and found that the number of outbreaks is increasing - and of those who contracted the illness, nearly 70 percent were unvaccinated.

The anti-vaccination movement has been growing in recent years, partially thanks to a dishonest 1998 study by since discredited former physician Andrew Wakefield, who was struck off the UK medical register for misconduct.

Wakefield's study used deliberately falsified results to make the fraudulent claim that there was a link between vaccines and autism.

Although subsequent research has found that there is absolutely no link between vaccines and autism, never mind a causal one, many still believe it and refuse to vaccinate their children, including the important measles, mumps and rubella, or MMR vaccine.

Thanks to this vaccine, researchers from the US Centers for Disease Control and Prevention say, endemic - that is, constantly present - measles has been eliminated from the US.

However, cases are still being imported from outside the US, and it's from these that outbreaks start.

The 1,789 cases of measles in US residents examined by the CDC team were all the documented cases for the time period. Incidence of measles is relatively low in the US compared to the worldwide rate of 40 cases per million people annually.

 

However, it definitely grew in the US over time, from 0.28 cases per million people in 2001 doubling to 0.56 cases per million in 2015.

Of 2,012 cases overall - including those reported by visitors to the US - only 535 were imported. That leaves 1,477 cases of measles that were contracted within the country.

And for cases contracted by US residents, 1,243 were unvaccinated. That's a massive percentage - 69.5 percent. A further 17.75 percent had unknown vaccination status.

The illness is a serious one, and the most vulnerable segment of the population are unvaccinated infants and toddlers, who are at a higher risk of fatal complications. The researchers found that the incidence of measles does decline with age, which highlights the importance of protecting small children.

Although the study did have a limitation based on the inability to verify vaccination information for the adult cases, it's not the first time that failure to vaccinate has been linked with measles outbreaks.

Moreover, previous modelling suggests that failure to vaccinate can have negative effects on the broader community, which doesn't just mean outbreaks - it also means increased load on hospitals.

 

Although vaccinated people can contract measles, the CDC's research suggests that vaccination drastically lowers the risk.

"The declining incidence with age, the high proportion of unvaccinated cases, and the decline in the proportion of vaccinated cases despite rate increases suggest that failure to vaccinate, rather than failure of vaccine performance, may be the main driver of measles transmission, emphasizing the importance of maintaining high vaccine coverage," the researchers wrote in their paper.

The research has been published in The JAMA Network.

 

More From ScienceAlert