How misinformation is fuelling the current measles crisis

With measles cases spiking amid falling vaccination rates in many parts of the world, it’s important to fight vaccine hesitancy alongside ensuring better access to vaccines.

  • 26 January 2024
  • 6 min read
  • by Gustavo Corrêa
A man reading "fake news" on a tablet. Credit: memyselfaneye from Pixabay
A man reading "fake news" on a tablet. Credit: memyselfaneye from Pixabay



In 2016, the UK had a major public health win when the World Health Organization (WHO) declared it had eliminated measles. But two years later this status was revoked as cases doubled. Now, the UK is in the midst of a measles emergency with 140 cases reported so far in 2024 alone. How did the country go from elimination to emergency?

While some health experts argue that vaccine hesitancy is not to blame, trends in vaccination suggest the answer is more complicated. While many factors are at play, what is clear is that misinformation is undoubtedly a major threat in spreading killer childhood diseases like measles.

There is a vaccine that is safe and is 97% effective – just two doses offer lifelong protection – yet, despite this, vaccination rates have been falling in some parts of the world for years.

The emergency in the UK is mirrored across the globe. WHO issued a warning this week that there has been a 45-fold rise in cases in Europe. More than 42,200 cases were reported in 2023, compared with 941 cases in 2022.

This rise follows a trend. Measles outbreaks are being reported across Africa and Asia, with Gavi supporting major vaccination campaigns to stop the spread of the disease. Global measles cases in 2022 were up by 18% and deaths by 43% compared to 2021. In 2022, there were 9 million cases and 136,000 deaths (compared to 90,000 deaths in 2016).

The measles virus is incredibly contagious, with an R0 number of 18. This means that if the disease runs unchecked, one person will infect around 18 or more other people. Children tend to be most affected. Measles is a serious disease that can infect the respiratory tract and spreads throughout the body, potentially causing pneumonia or encephalitis (swelling in the brain).

The good news is that there is a vaccine that is safe and is 97% effective – just two doses offer lifelong protection – yet, despite this, vaccination rates have been falling in some parts of the world for years. The UK Health Security Agency has declared measles a national incident not just because are cases rising, but because MMR (measles, mumps and rubella) vaccinations have fallen, leaving 3.4 million children under 16 at risk across England, according to UK NHS (National Health Service) data. And worldwide, the picture is far worse – one in five children globally haven't received a single measles vaccine.

The challenge with low vaccination rates is  if less than 95% of children are vaccinated, there will not be the herd immunity required to stop the virus spreading and to achieve and maintain measles elimination. Currently, on average globally, only 81% of children have received the first dose of vaccine and only 71% the second dose. In the UK, 87% have had both doses and in London this drops even lower to 74%.

It's that a key factor in the current outbreak is that many children missed out on routine measles immunisation doses during the COVID-19 pandemic, leaving them vulnerable to infection. And in countries such as England, experts point to healthcare d causing challenges in accessing vaccines.

However, measles vaccine coverage has been falling in the UK since before COVID-19, indicating that disruptions due to the pandemic aren't the only reason.

We also cannot ignore growing vaccine hesitancy, which is especially relevant in high-income countries. Well before the pandemic, vaccine hesitancy was identified by WHO as one of the biggest threats to human health. The reluctance of some people to take COVID-19 vaccines despite the significant risk that the disease posed to their health exemplified how hesitancy has taken root.

What is herd immunity?

Pathogens such as viruses and bacteria survive by constantly infecting new hosts. If everyone in a population is immune to a pathogen, then it will have nowhere to go and will eventually die out. This is herd immunity – also known as herd protection or community immunity – and it is one way in which vaccines help to prevent the spread of infectious disease.

Vaccines protect individuals by training their immune systems to recognise and destroy specific pathogens, without them needing to become infected themselves. However, vaccines also help to protect other people by reducing the number of susceptible individuals in a population and making it harder for pathogens to find new hosts.

Herd immunity is particularly important for protecting people who have weak immune systems and may not be able to receive certain vaccines, such as newborn babies, elderly people and those with diseases or who are undergoing medical treatments that suppress the immune system.

The proportion of the population that needs to be vaccinated to achieve herd immunity varies between different diseases and types of vaccine. For instance, measles, which is extremely contagious, requires around 95% of people to be vaccinated to prevent outbreaks, while the herd immunity threshold for polio is around 80%.

There are also certain diseases, such as influenza or COVID-19, where herd immunity may be unattainable because the pathogen rapidly mutates or the vaccine provides only partial protection against infection.

Even if herd immunity thresholds aren’t reached, the greater the proportion of people who are vaccinated, the slower infections will spread through communities. However, sometimes disease outbreaks occur in countries or regions with high vaccination rates.

This is because, even in highly vaccinated populations, there may be communities or geographical areas where vaccine uptake is lower for various reasons. If an infection occurs in one of these communities, it can quickly spread, putting lives and livelihoods at risk – including those of vulnerable individuals who cannot be vaccinated or whose immune systems respond only weakly to vaccines.

This is why it is important to take up the offer of vaccines if they are available to you: not only do they reduce your own risk of disease, they also help to protect those around you.

In the UK, however, mistrust in vaccines had been sown decades ago by a flawed paper published in The Lancet with Andrew Wakefield as the lead author, that stated a link between the MMR vaccine and autism. This has now been thoroughly debunked as false, but the hesitation it triggered may have lingered.

The anti-vaccination movement is being fuelled by misinformation that circulates in communities and is boosted by the internet and social media. Information posted on forums and social media channels can often be unreliable, and people often may lack the ability and tools to appraise what can be trusted.

So, how do we counteract this?

First, ensuring that routine immunisations reach the children who need them is critical. Every effort should be made to ensure the vaccine is available and ready to use with special attention for specific communities with lower vaccination rates and facing access issues. Basically, if people come looking for vaccines, it's the responsibility of health authorities to ensure they can access them.

On the outbreak containment side, there is a need to introduce targeted responses, which may include the quarantine of cases and people they have been in contact with. Measles is a challenging disease to control because of its high transmissibility, and also due to the fact that children are contagious several days before they are symptomatic, so quarantine measures may reduce the speed of spread and buy precious time, but likely won`t be enough. Targeted immunisation campaigns should also be prioritised, as this will be critical in decreasing the susceptible population and reducing transmission of the virus.

Finally. we need to increase vaccine demand and reassure people that vaccines are safe and effective. To do so, public health officials need to increase and improve communication across the media to counter vaccine misinformation. We need to urgently increase community engagement – especially with communities with high numbers of unvaccinated children – to better tailor approaches and address concerns and key drivers for low immunisation rates.