Measles: WHO has declared it an ‘imminent global threat’

 Reduced access to routine healthcare and lower immunisation rates were two effects of the epidemic. As a result, the measles was deemed a "imminent concern in every corner of the world" by the World Health Organization in November 2022. In 2021, a record number of around 40 million kids missed at least one dose of the measles vaccine, according to their account.

A respiratory virus causes measles. Similar to COVID, transmission is fueled by respiratory droplets and aerosols, which are transmitted from person to person (airborne transmission). In mild cases, the infection causes a rash and fever.

However, severe cases can result in pneumonia, blindness, and encephalitis (brain swelling). There are roughly 128,000 fatalities every year and 9 million cases. 

The measles vaccine is quite effective, and it can be given alone or in conjunction with other shots like the mumps and rubella vaccines to form the MMR immunisation. The majority of nations use a two-dose regimen, with the first shot typically administered at 12 months and the second shot at 4 years old.

The vaccine offers highly strong and long-lasting protection, and is a prime example of a disease that can be prevented through vaccination. A two-dose regimen provides approximately 99% protection from measles infection.

One in ten people who contract the measles die from it in developing nations where vaccination rates are low. In wealthy nations, the majority of measles deaths—roughly one among 1,000 to 5,000 cases—occur in unvaccinated individuals.

There is a considerable risk of new outbreaks of diseases that can be prevented by vaccination in places like conflict zones and among populations of refugees. Malnutrition issues significantly increase the likelihood of developing a serious illness, and respiratory infectious infections are a major concern for humanitarian organisations that serve vulnerable populations like Ukrainian refugees.

The measles is extremely contagious. Its basic reproduction number (R0), or how many individuals an infected person would typically go on to infect in a susceptible community, is predicted to range between 12 and 18. For comparison, it is estimated that the R0 of the omicron COVID version is close to 8.2.

The herd immunity threshold is the percentage of a population that must receive vaccinations to prevent outbreaks and reduce subsequent transmission within a community (HIT). The HIT magic number for measles is commonly thought to be 95% vaccination coverage.

With a global coverage of roughly 71% for two doses and 81% for one dose, the majority of the world is much below that cutoff. 

Even if children survive measles, there is a possibility of long-term damage to their immune system, described as a “form of immune amnesia”. In unvaccinated populations, a severe case of measles resulted in an average loss of 40% of antibodies that would normally recognise germs.

After a mild case of measles, unvaccinated children lost 33% of those antibodies. By comparison, measurements in healthy control populations indicated an antibody loss of 10% over similar or longer durations.