New research highlights lasting immune damage caused by measles infection

Scientists reveal that measles can erase immune memory, increasing vulnerability to other infections long after recovery, amid rising cases globally.

Measles has long been known to do more than trigger fever, rash and cough. Doctors have observed for more than a century that the infection temporarily weakens the immune system, leaving children more vulnerable to problems such as ear infections, diarrhoea and, in severe cases, pneumonia. But newer research suggests the damage can last far longer than the acute illness itself, reshaping how the body responds to later infections. According to reporting by The Washington Post and supporting research indexed in PubMed, scientists now describe this effect as measles-induced “immune amnesia”.

The idea is simple but unsettling: measles can strip away part of the immune system’s memory. During childhood, the body builds up a record of past encounters with viruses and bacteria through B cells, T cells and antibodies. That memory is what helps the immune system react quickly the next time a familiar germ appears. But studies have found that measles can erase a large share of that protection. Research summarised in PubMed and Harvard Magazine indicates that the virus attacks pre-existing immune memory, reducing the diversity of B cells and destroying cells that help the body recognise earlier threats.

A 2015 study published in Science went further by looking at decades of child mortality data from the United States, England and Wales, and Denmark. Researchers found that before vaccination became widespread, increases in measles cases were followed not just by more deaths from other infections right away, but by elevated mortality for two or three years afterwards. That pattern did not appear with other vaccine-preventable illnesses in the same analysis. The study’s authors estimated that, in places where measles was common, the virus may have been linked to as much as half of all infectious-disease deaths in children. Other research has since supported the same broad conclusion: measles can suppress immunity in ways that outlast the initial infection.

The consequences are not merely theoretical. Reporting from The Washington Post said children who recovered from measles in Berlin during the 2014-15 outbreak were later more likely to return to hospital with a different infection than children in comparison groups. PubMed-indexed research has also suggested that measles may destroy memory cells carrying earlier immune information, helping explain why some people become more susceptible to unrelated illnesses after recovery. Historical work has even argued that the phenomenon was recognised long before modern immunology gave it a name, with evidence that measles-related immune weakening was noted as far back as the 18th century.

That matters now because measles is spreading again in some places. The Washington Post reported that the United States had already recorded more than 3,800 cases this year, well above the total reported in 2025. Measles is extraordinarily contagious and can remain in the air for up to two hours after an infected person leaves a room. Public health experts say two doses of the MMR vaccine offer about 97% protection, and vaccination remains the most reliable defence against both the infection itself and the longer-term immune damage it can cause.