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Measles vaccine protects against other deadly diseases.

A new study suggests that, vaccinating kids against measles could protect them from other diseases as well. Image Courtesy :-SCIENCE SOURCE.

According to World Health Organization (WHO) facts, measles kills about 140,000 people worldwide every year, but the millions of kids who have survived the disease aren’t in the clear.

Measles :-

  • Measles, also known as morbilli, rubeola, or red measles, is a highly contagious infection caused by the  measles virus.
  • Initial signs and symptoms typically include fever, often greater than 40 °C (104.0 °F), cough,runny nose, and red eyes.
  • Measles is an airborne disease which spreads easily through the coughs and sneezes of those infected. It may also be spread through contact with saliva or nasal secretions.

A new epidemiological study suggests that they remain susceptible to other infections for more than 2 years, much longer than researchers anticipated. The result suggests a hypothesis that the measles virus undermines the immune system’s memory and indicate that the measles vaccine protects against other deadly diseases as well.

Since time, researchers have long known that measles inhibits the immune system. But previously they thought this effect wore off after a few months at the most. However, recent studies of children in developing countries, where most cases occur, found that measles vaccination reduces the overall death rate from infections for up to 5 years, suggesting that preventing the disease somehow provides protection against other illnesses.

Mechanism:-

  • One possible explanation for this benefit is that the measles vaccine somehow enters the immune system to produce defenses against these other diseases. But after research on monkeys recovering from measles gave an alternative hypothesis.
  • In 2012, Rik de Swart of Erasmus MC in Rotterdam, Netherlands, and colleagues revealed that the measles virus kills large numbers of memory cells, white blood cells that prevent subsequent infections by the same pathogen. Thus, the measles virus might cause what the scientists termed immunological amnesia, impairing the immune system’s ability to remember and quickly eliminate other microbes it has already beaten. According to Michael Mina, lead author of the new  research paper and a medical student at Emory University School of Medicine in Atlanta “you are vulnerable to diseases you should not be vulnerable to”.

Research Data  and Findings:-

  • De Swart and Mina, a postdoc at Princeton University, obtained data on the numbers of measles cases and deaths from other infectious diseases in the United States, Denmark, and part of the United Kingdom. Measles vaccination started in the 1960s in the United Kingdom and United States and in the 1980s in Denmark, and the researchers had statistics from before and after its introduction.
  • The team’s mathematical analysis tried to determine whether there was a relationship between the number of measles cases and the number of kids who died from other diseases. If the virus inhibits immunity for only a short time, for example, the number of deaths from other infections in a specific year might correlate to the number of measles cases in that year. But if the virus triggers a prolonged immune amnesia, the number of deaths in a particular year might correlate to the total number of cases in that year and the previous year or two.
  • Using this approach, the researchers calculated that children who survive measles remain vulnerable to other diseases for an average of 2.5 years. The value was almost the same for all three countries, the team reports online today in Science. According to Mina, “Our results suggest that the adverse effects of measles are much more lasting”.
  • To check that the immune impairment resulted from measles, the researchers analyzed statistics for whooping-cough, which doesn’t suppress the immune system. They found no link between the number of whooping-cough cases and mortality from other infectious diseases.
  • Mina and his colleagues also determined that the length of susceptible period didn’t change in any of the three countries after introduction of vaccination. That finding supports the idea that the measles vaccine benefits children not just because it prevents them from getting measles, but also because it provides protection against the other diseases. In the days before vaccination, measles was responsible for about half of childhood deaths from other illnesses, the team reports. With that many dead children, why didn’t researchers detect this connection before? Many assumed that measles’ impact on the immune system quickly faded, team suggests.
  • So when a kid gets pneumonia 6 months later, nobody would link that to measles. Other studies of children in West Africa didn’t show a lasting “measles shadow.” Mina and colleagues note that half of the kids in these studies died from other diseases within 2 months after they had measles, which would have made it difficult to detect a long-term effect.
  • Vaccine immunologist Katie Flanagan of Monash University in Melbourne, Australia,  added that, ” There could be a prolonged immunosuppression is possible”. But the study “is a long way from really proving it.” For example, researchers need to show that the kids who had measles are the ones dying from other illnesses.
  • according to William Moss, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland,“It is indirect evidence”. But he says that the results are “highly suggestive” that measles is contributing to this longer period of immunosuppression. And if the researchers are right, he says, “the benefits of measles vaccination are far greater than simply the reduction in measles deaths.”

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