The immune system is extremely clever, and has the ability to remember every pathogen that it has ever had to deal with so that it can quickly defeat any repeat invaders. Vaccinations are also very clever, and harness this ‘immune memory’ to protect us from all sorts of diseases. Not getting vaccinated, however, is not clever at all, especially given the latest research revealing how catching measles could have catastrophic consequences for the entire immune system.

As highlighted by Science News, researchers are beginning to understand how the measles virus continues to damage a person’s health long after the acute effects of the infection have passed. By attacking the immune system’s memory cells, the virus actually erases the body’s back catalog of past infections, leaving it open to invasion by a host of pathogens that it had previously learned to fight off.

Like a particularly spiteful hacker, the measles virus not only causes immediate damage in the form of symptoms, but it also disables the body’s security system, leaving the door wide open for other malevolent microbes to have a free-for-all.

Researchers began to suspect that measles may be causing ‘immune amnesia’ when studies on non-human primates showed that animals that had been infected with the virus suffered depleted stores of memory lymphocytes. This started to make more sense when a paper published last year revealed that as the measles virus spreads to different parts of the body, it tends to make a beeline for the nearby immune system cells.

Subsequent research conducted in the Netherlands showed that unvaccinated children also experienced a massive drop in these memory cells if they contracted the illness.

Scientists don’t yet know how long it takes the immune system to recover from this amnesia, but one study that looked at 2,228 child patient records showed that kids who had had the measles remained at an increased risk of other illnesses five years later. Compared to those who had never had the virus, children with the measles were 43 percent more likely to contract another infection within one month, and were between 15 and 24 percent more likely to require an anti-infective prescription over the next half-decade.

Based on this data, study co-author Rik de Swart told Science News that “wherever you introduce measles vaccination, you always reduce childhood mortality. Always.” While the acute symptoms of measles itself are very rarely fatal, the virus’ lingering legacy massively increases the chances of catching something much more severe further down the line.

Like the immune system itself, therefore, the measles virus is turning out to be very clever indeed. Certainly cleverer than anti-vaxxers.