Measles can occur in babies under 6 months of age

In measles, nest protection diminishes faster than previously assumed

03.02.2020

In infants under one year of age it is often assumed that they are at least temporarily immune to measles, as maternal antibodies are transferred to them during pregnancy (so-called nest protection). However, new studies suggest that this nest protection in babies already wears off at the age of 3 months.

For the study, Canadian researchers examined the measles antibody levels in their blood samples in 196 infants under twelve months of age. In infants aged one month, they found that 20% of children had antibody levels below the protective threshold. In the three-month-old infants, 92% were already below this threshold. In fact, by 6 months of age, all infants lacked adequate measles immunity based on antibodies in their blood. According to the researchers, the amount of time previously assumed for maternal measles antibodies to protect infants is often based on studies done in people around whom measles was still prevalent. Pregnant women who are immune to measles from vaccination may not have the same level of antibodies as women who are immune from previous infections, among other things. Many infants are therefore susceptible to measles in their first year of life until they receive their first dose of vaccine, according to the authors. In many countries, including the USA and Canada, as well as Germany (first combined vaccination against measles, mumps and rubella at the age of 11 to 14 months, second vaccination at 15 to 23 months of age), the vaccine is routinely administered from age 12. Dosed at 6 months of age based on a child's risk of contracting measles and a child's ability to respond to the vaccine. The authors said recent results underscore the importance of vaccination around infants to protect them from measles. Because measles can cause serious complications such as pneumonia, inflammation of the brain (encephalitis) and death.

Source: AAP News, Pediatrics