Ancient pathogen is an ‘imminent threat’ in every part of the world, WHO warns: ScienceAlert

One of the consequences pandemic he was reduced access to routine health care and a lower level of vaccination. As a result, in November 2022 World Health Organization declared measles to be “an imminent threat in every region of the world”.

They described how a record number of almost 40 million children missed receiving at least one dose of the measles vaccine in 2021.

Measles is a viral respiratory disease. Transfer it is similar to COVID, except that it spreads between people through respiratory droplets and aerosols (airborne transmission). The infection causes a rash and fever in milder cases.

But difficult cases can include encephalitis (swelling of the brain), blindness and pneumonia. There are approx 9 million cases per year and 128,000 deaths.

The measles vaccine, which can be given alone or in combination with other vaccines such as mumps and rubella in addition to MMR immunization, is very effective.

Most countries have a two-dose schedule, with the first injection usually given at 12 months of age and the second dose when the child is four years old.

The vaccine provides very high and long-lasting protection and is truly a prime example of the term “vaccine-preventable disease.” Two-dose schedule gives about 99 percent protection against measles infection.

In developing countries where the receipt of vaccines is low, even one out of ten those who get measles die from it. In developed countries, deaths are mostly among unvaccinated people rate about one in 1,000 to 5,000 measles cases.

The possibility of new outbreaks of vaccine-preventable diseases in areas such as conflict zones and among refugee population is high.

Problems such as malnutrition greatly increase the risk of serious diseases, and respiratory infectious diseases are a a huge concern for humanitarian groups supporting vulnerable groups such as Ukrainian refugees.

Measles is incredibly contagious. His basic reproduction number (R0) – that is, how many people on average one infected person will infect in a susceptible population – is estimated be between 12 and 18. For comparison, the R0 omicron of the COVID variant is thought it was around 8.2.

The proportion of the population that needs to be vaccinated to keep outbreaks under control and to reduce further transmission in the community is known as the herd immunity threshold (HIT).

For measles, vaccine coverage of 95 percent is usually considered the HIT magic number.

Most of the world is far below that threshold, with global coverage of about 71 percent for two doses and 81 percent for one dose. In Great Britain, 2021-22 data shows that 89 percent of children received one dose of measles vaccine.

Globally, there has been significant progress in reducing deaths from all causes in children under the age of five. The annual number of deaths decreased from 12.5 million in 1990 to 5.2 million in 2019. However, low vaccination coverage could reverse these gains.

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 an unvaccinated population, a severe case of measles resulted in an average loss of 40 percent antibodies which would normally recognize germs.

After a mild case of measles, unvaccinated children lost 33 percent of those antibodies. For comparison, measurements in a healthy control population showed antibody a loss of 10 percent over similar or longer periods.

Misinformation is widespread

Anti-vaccine advocacy has fueled false rumors and scare stories, such as false claims former doctor and anti-vaccine activist Andrew Wakefield that the MMR vaccine causes autism.

This belief persists. For example, a US Population Survey 2020 found: “18 percent of our respondents incorrectly say that it is very or somewhat true that vaccines cause autism.”

Misinformation since the beginning of the COVID pandemic is was extensive. And there is a risk that this misinformation will further translate into higher levels of vaccine hesitancy and refusal routine immunization.

Measles spreads easily and is a serious infection in the short and long term in unvaccinated populations. There is a great need for vaccination campaigns for increasing protection against vaccine-preventable diseases, worldwide.

The need is particularly urgent in developing countries and among other vulnerable populations such as refugees and conflict areas.

Michael Headsenior research associate for global health, University of Southampton

This article was republished from Conversation under Creative Commons license. Read Original article.