The World Health Organization says Europe is battling a serious outbreak of measles. More than 41,000 adults and children were infected during the first six months of 2018. That's up a disturbing 71 per cent over all of 2017.

The WHO says Serbia, Ukraine, Georgia and Greece are the top four countries hardest hit so far. Next on the list are Romania, Italy and France. Slovakia, Russia and the United Kingdom round out the top ten. Authorities in the UK say that country has had over 800 confirmed cases. There have been 37 deaths across Europe.

In most of these countries, the majority of those infected have been children and teenagers. That suggests the cause is related to unvaccinated and under-vaccinated children.

The outbreaks across Europe are an ocean away from Canada, but that doesn't mean we should not be vigilant. As reported by CBC News, Fraser Health has issued a warning after a person with measles reportedly visited a New Westminster pool last week. Officials there say anyone at the Moody Park Outdoor Pool on Sunday, August 19 between 1:30 p.m. and 4:30 p.m. PT may have been exposed to the virus.

And health officials with the BC Centre for Disease Control reported earlier this month that a teenager infected with the measles virus traveled through the Vancouver airport on July 30 and on August 6. They issued an alert urging those who may have been in contact with the teen or who used the airport on those days to make certain they've been immunized against the measles.

It's likely that both of these cases originated in measles hotspots.

I'm also keeping an eye on the U.S., where the Centers for Disease Control (CDC) reports at least 107 cases of measles have been confirmed across 21 states. In all of 2017, the U.S. had 118 cases across 15 states, so it appears that measles may also be on the rise south of the border. A lot more people travel between Canada and the U.S. than Europe. Any significant outbreak in the U.S. is likely to have an impact on public health in this country.

The disturbing rise in cases of measles in Europe is not new. We talk about vaccine hesitancy being a big problem in Canada and the U.S., but scepticism about the effectiveness and safety of vaccines is particularly high in parts of Europe.

A 2016 survey found Europe had among the lowest rates of public confidence in vaccines in the world. France and Italy had very high rates of scepticism about vaccine safety. But it's not just Europe; the survey found Canada, the U.S., and Mexico had higher levels of concern about the safety of vaccines than China, Japan, Hong Kong, and countries in South America.

In France, vaccine scepticism can be traced to a national hepatitis B vaccination campaign that was suspended in 1998 amid concerns about side effects. In the U.K., it came directly from a 1998 paper (since retracted because of fraud) that alleged a link between MMR vaccine to autism. The impact of the original paper continues to be felt. Vaccination rates in the U.K. dropped, and have not recovered to previous levels despite the paper's retraction.

Social media is the new factor influencing public opinion on vaccines. You've heard about Russian social media bots that spread fake news and attempted to influence the outcome of the 2016 U.S. presidential election, as reported in the New York Times. A study published last week in the American Journal of Public Health found the same tactics used to spread fake news about vaccines.

U.S. researchers examined thousands of tweets sent between 2014 and 2017. They discovered several accounts that belong to the same Russian trolls that operated during the U.S. election. They found that many of the anti-vaccine tweets come from bot accounts or hacked accounts taken over by bots. These accounts shared anti-vaccination messages 75 per cent more than average Twitter users.

The researchers reviewed more than 250 tweets about vaccination sent by an account linked to the Internet Research Agency, a company backed by the Russian government and implicated in the 2016 election. They found tweets that linked vaccination to racial disparities and concluded that trolls use vaccination as a wedge issue that promotes discord in American society.

I'm not sure how best to address fears about vaccines. Some say public health education campaigns are one way to sway public opinion in favour of vaccinations. Financial penalties are another approach. Earlier this year, the Australian government said it would issue monthly fines to parents who don't have their children immunized.That's in response to a significant increase in the percentage of parents who haven't vaccinated their kids on the basis of a conscientious objection. It's too soon to tell how successful that measure will be.

France is moving toward mandatory vaccination of children. Italy is moving in the opposite direction and abolishing a law that makes vaccination mandatory for children before they start school. The amendment means parents of unvaccinated children will no longer face fines.

The damage to public health and safety caused by the measles virus is already enormous. I worry that bots and troll accounts are raising levels of vaccine hesitancy even more. Left unchecked, they will lead to even larger outbreaks. We need to get a handle on these new tactics before a lot more damage is done to public health.