(CNN) The United Kingdom says it will take steps to halt the spread of misinformation about vaccines as a result of losing its "measles-free" status after the highly infectious disease was declared eliminated in the country three years ago.
Measles, which is almost entirely preventable with two doses of vaccine, is making a comeback globally. In the first half of the year, there have been almost three times as many cases as the same time last year. Cases globally are at the highest level since 2006, according to the World Health Organization.
"After a period of progress where we were once able to declare Britain measles free, we've now seen hundreds of cases of measles in the UK this year. One case of this horrible disease is too many, and I am determined to step up our efforts to tackle its spread," Prime Minister Boris Johnson said in a statement.
"This is a global challenge and there's a number of reasons why people don't get themselves or their children the vaccines they need, but we need decisive action across our health service and society to make sure communities are properly immunized."
Johnson said that that he would summon social media companies "to discuss how they can play their part in promoting accurate information about vaccination." He also said people would be encouraged to have catch-up vaccinations.
Social media has made it easier for vaccine opponents to operate although the pushback on immunization among some groups isn't the only reason behind the upsurge in the disease. Poor access to quality health care, displacement due to conflict, complacency and a lack of awareness also play big roles, according to WHO.
In Europe there have been close to 90,000 cases reported for the first six months of this year, exceeding those recorded for the whole of 2018, while the United States has reported its highest measles case count in 25 years, according to WHO.
The UK isn't the only country taking steps to stop the spread of the disease, which can spread through the air when an infected person coughs or sneezes. Last month, Germany made measles jabs mandatory for children entering school or kindergarten. Parents will be required to provide evidence that their child has been vaccinated before they are enrolled, and will face fines of up to 2,500 euros ($2,800) if they fail to do so.
Johnson called for renewed efforts to meet the 95% WHO target for both doses of the MMR vaccine, which protects against measles, mumps and rubella. While the UK meets the target for the first dose of the jab, currently, only 87% of children in the UK are getting their second dose, which has likely contributed to the spread of measles.
The UK was deemed to have eliminated measles by the WHO in 2017, based on data from 2014-2016, according to Public Health England, a government body.
In countries that have eliminated measles, measles cases can still occur, but these will be isolated cases that only have limited spread within the community -- typically meaning only outbreaks that had started abroad and were then passed on.
However, in 2018, there was a marked increase in the number of confirmed measles cases, with 991 confirmed cases in England and Wales, compared with 284 cases in 2017. According to the WHO, in 2019 there were 489 confirmed cases in the UK as of August 7.
Furthermore, the same strain of measles virus (called B3 Dublin) was detected for more than 12 months across 2017 and 2018, the body said.
"Based on this, WHO determined that the UK could no longer be consider as 'eliminated' and that transmission of measles had been re-established," Public Health England said.
"Losing our 'measles-free' status is a stark reminder of how important it is that every eligible person gets vaccinated. Elimination can only be sustained by maintaining and improving coverage of the MMR vaccine," added Dr. Mary Ramsay, head of immunization at Public Health England.
WHO has deemed vaccine hesitancy -- the reluctance or refusal to vaccinate despite the availability of vaccines -- a top 10 threat to global health in 2019.
"We are still suffering from the now entirely debunked MMR scandal of the nineties, and it is potentially disastrous that as a result so many young people are now susceptible to serious, often life-threatening infectious diseases, such as measles, that we could have completely eradicated in this country if this had never happened," said Prof. Helen Stokes-Lampard, chair of the Royal College of General Practitioners.
"People who were not vaccinated as children need to understand that it is not too late to have their MMR jab and we would urge them to do so."
Numerous studies have dismissed claims that measles vaccinations cause or trigger autism.