Why measles is on the rise in the world, and why it’s a real problem – Edition du soir Ouest-France

By Raúl RIVAS GONZÁLEZ, Professor of Microbiology, University of Salamanca (Spain)

Measles cases have skyrocketed in recent years around the world. The lack of confidence in vaccines and the Covid-19 pandemic and they are for a long time. The consequences are serious.

We often tend to think that redness is a disease of the child certainly annoying with these red plaques that have discovered progress throughout the body, more harmless and has been defeated. Wrong: it is a serious, highly contagious viral disease (a contaminated person can infect another 15 to 20; it is contagious before the rash and five days later on average) and easily transmitted. It can be contracted at any age and can lead to serious complications – sometimes fatal.

That is why we need to be concerned that between 2016 and 2019, the number of reported measles cases in the world increased by 556% to 869,770, the highest number since 1996. More than 140,000 people died in 2018, mostly children under the age of 5. A tragedy all the more discouraging as it could have been largely avoided.

Moreover, between 2018 and 2020, a measles epidemic in the Democratic Republic of the Congo infected more than 460,000 children and caused nearly 8,000 deaths.

The rise continues and the UN has already warned that measles cases will increase by 79% worldwide in the first two months of 2022. Between September 2021 and February 2022, Somalia reported 5,760 cases of measles, Nigeria 5,613 cases, India 4,178 cases, Ethiopia 1,979 cases, Pakistan 1,861 cases and so on. We could thus continue to list the countries affected by thousands of infections. This is very bad news.

She was thought to have been eradicated, but she is coming back

Some Western countries are also following this trend. In 2000, the United States of America declared measles removed from its territory. However, in 2019, nearly 1,300 cases of measles were reported in 31 states, the highest number since 1992. What is happening?

The analysis of the 2018-2019 measles epidemic in New York, the largest in the country for almost three decades, has identified the factors behind this unexpected magnitude: action has been taken in the occurrence of late vaccination of young children combined with increased contact between them… probably during “measles parties” organized to deliberately infect children.

Infections occur mainly in infants 1 to 4 years of age and infants under one year of age. To contain the epidemic, the New York City Department of Mental Health and Hygiene has launched extensive immunization campaigns and ordered mandatory immunization of anyone living, working, or attending school in the codes concerned.

As a result of this voluntary policy, between October 2018 and July 2019, more than 32,000 people under the age of 19 were vaccinated against measles, mumps and rubella (MMR). And the epidemic has subsided.

Further analysis suggests that without vaccination campaigns, the epidemic could infect between 6,500 and 8,100 people compared to 649 actual cases.

Let’s be clear: these “measles festivals” are a senseless and dangerous practice that must be eradicated.

The French do not trust vaccines

Prior to the introduction of the measles vaccine in 1963 and the widespread spread of vaccination, major global epidemics occurred every 2 to 3 years or so and caused some 2.6 million deaths per year. Between 2000 and 2018, vaccination prevented around 23.2 million deaths.

Despite the evidence, a global survey of 67 countries published in 2016 found that confidence in vaccine safety in France was the lowest in the world. This increases the risk of infectious epidemics, including measles. Perhaps because of this issue, measles cases in France amounted to 2,637 in 2019. [Entre 2008 et 2020, sur les plus de 30 000 cas déclarés en France, 1 700 personnes ont développé une pneumopathie grave, 42 une complication neurologique (39 encéphalites, 1 myélite, 2 Guillain-Barré) et 26 sont décédés, NdlR.]

Fortunately, according to 2020 data, confidence in the interest and safety of the measles vaccine has increased significantly in a large number of countries. Generally, in the European Union, it is considered to be high.

In Spain, confidence in vaccines is good. The MMR (measles, rubella, and mumps) vaccination program was introduced in 1981. The MMR vaccine contains live attenuated measles and mumps viruses prepared in cell cultures of chicken embryos. It also contains live rubella attenuated virus prepared in human lung cells (more precisely fibroblasts).

Its still high vaccine coverage allowed Spain to be declared free of endemic measles transmission in 2014. In 2017, the World Health Organization for Europe declared measles eliminated from the country after absence of endemic transmission for a period of at least 36 months. Since then, cases and epidemics of measles signals have always been imported or linked to import.

Diversity of the measles virus

WHO recognizes 24 red virus genotypes (A, B1, B2, B3, C1, C2, D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, E, F, G1, G2, G3, H1 and H2), divided into eight clades (AH). Despite this heterogeneity, all are considered to belong to one major type. Most vaccine strains are derived from the Edmonston strain (genotype A) isolated in 1954 and are effective against all others.

Currently, only three of these 24 known genotypes are responsible for epidemics in the world: the H1 genotype, which is endemic to China; B3, mainly present in African countries (from which it originates); and the D8 genotype, which appeared in Asia in the 1980s but is now widespread around the world.

Genotypes D8 and B3 are responsible for epidemics in recent years in Europe, Asia and North America.

The impact of the Covid-19 pandemic

Unfortunately, the measures taken to curb one epidemic can have detrimental consequences on another. Thus, the Covid-19 pandemic has had a serious impact on vaccination programs and red surveillance systems in numerous payments.

In March 2020, the World Health Organization (WHO) issued guidelines stating that mass vaccination campaigns should be suspended in order to maintain physical distance and minimize coronavirus transmission.

Or, the interruption of vaccination services, even for short periods, has had the effect of increasing the number of sensitive individuals and communities where protective coverage is less than 95% (rate to be achieved to obtain collective immunity against virus what the). The result was a worldwide increase in red epidemics.

It is estimated that a 15% reduction in routine measles vaccinations could increase the number of child deaths by nearly 250,000 in the poorest countries. The suspension of these mass vaccination campaigns is especially pernicious in countries caught in a conflict. Among others because malnutrition of children and mothers is then more common, which increases mortality from infection.

A disease that is not without danger

Although vaccination and good medical care couldnt reduce the likelihood of serious complications, measles-related deaths and hospitalizations due to complications occur even in developed and industrialized European countries. [Les complications se produisent dans 30 % des cas et sont plus lourdes chez les personnes immunodéprimées, les nourrissons et les adultes de plus de vingt ans. Elles vont de l’otite et la diarrhée à des atteintes du foie, des reins, des poumons ou des yeux. Dans un cas sur mille, on observe des complications neurologiques, une encéphalite par exemple, NdlR.]

That is why the WHO recommends vaccinating children and sensitive adults for whom it is not contraindicated.

At present, there is no doubt that the measles vaccine is safe, effective, and inexpensive. It should be included in all national vaccination programs.

The original version of this article was published in Conversation.

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