Two new studies compared children with measles to vaccinated children to see how measles infection affects the immune system. Here is what researchers found.
Every parent wants their child to develop a healthy immune system, and many ask what they can do to help the process along. While the answer is not simple, in healthy children with mild common illnesses, the immune system typically handles itself amazingly well. It will come out of each illness with a set of dedicated immune memory B-cells and T-cells to respond on short notice to those pathogenic microbes in the future. One bacterial or viral encounter at a time, the child learns to navigate their way through a world full of microbes.
Some illnesses, unfortunately, have a way of killing or harming those who encounter them before the full immune response can kick in. For those illnesses, we give vaccines (where we have created them). Vaccines allow the body to go through the innate, or first stage, of immune response, and develop the longer term adaptive immune response, without getting sick and causing damage or death to the child. They do so through using weakened (attenuated) or dead (inactivated) forms of the bacteria or virus, which lets the child’s immune system learn how to respond without getting hurt. Vaccines are a genuine immune booster.
However, parents may have heard claims that “natural immunity” from measles infection is “superior” to immunity after measles vaccine. It’s true that a measles infection gives very long-lasting immunity – to measles. This very strong response to measles infection is why some claim the immunity after infection is superior to the immunity after vaccination.
However, it’s also true that after being infected with measles, children (and adults) have a higher rate of infections and death for up to three years, sometimes longer. 1 While the body creates a strong response to measles infection, measles infection brings a lasting loss of immunity to other illnesses. This is known as the measles paradox. Far from helping the immune system mature, measles kills immune memory cells and tears up the work that has been done, setting the child’s immune system development back. Way back.
The effects of measles: like untreated HIV
“If you took all of the immunological memory that HIV tears down when it’s untreated for 5 to 10 years, that’s what you see after one measles infection.”2
That’s how Michael Mina, PhD, of the T. Chan School of Public of Health of Harvard, described the findings on a recent study looking at how measles infection damages the immune system.3 Published in Science in November 2019, the study looks at how measles infection alters the immune system. The researchers also evaluated how the measles vaccine affects the immune system.
The results were sobering: children who had measles infection lost between 11% to 73% of their immune memory, leaving them as vulnerable to non-measles infections as untreated HIV patients would be. While other studies have shown that measles-infected children will eventually rebuild their immune system memory, it takes two to three years. And measles-suppressed immunity has to be rebuilt from scratch – by encountering the same viruses and bacteria again, and getting sick with them again. That means that allowing a child to get measles puts that child in double jeopardy – both from the measles, and then again when encountering illnesses for which they no longer have immunity. They must run the risks of infection twice, instead of only once.
Researchers have known for some time that children who had measles had higher rates of illness and death for two to three years following the infection. Pre-vaccine, it appears that 50% or more of childhood deaths were due to post-measles infections and complications. The suspicion was that measles suppressed the immune system, but researchers weren’t quite sure how this occurred.
When a measles outbreak hit the Netherland in 2013 3, a group of researchers, led by Michael Mina, worked with parents of unvaccinated children to evaluate their children’s immune system memory before and after measles infection. Drawing blood before and after lab-confirmed measles infection, the researchers used a test called VirScan to assess to how many different types of pathogenic microbes the children’s immune systems had developed a response. They also performed the VirScan test on blood samples from other control groups (none of whom had been exposed to measles). These control groups included healthy children of the same ages, adults who had blood samples drawn at about the same number of weeks apart (ten weeks), vaccinated children (before and after vaccination with the MMR), and unvaccinated children who remained uninfected.
The results showed that the measles-infected children lost significant amounts of “antibody diversity.” Meaning, the researchers noted a reduction in “antibody species” after measles infection. While they developed strong immunity to measles, they lost immunity to many other common pathogenic microbes, including those causing various respiratory infections, pneumonia, ear infections, influenza, and several herpesviruses (a family of viruses including the viruses for cold sores, mononucleosis, and cytomegalovirus)3. Meanwhile, none of the control groups lost antibody diversity or immune memory over the same time span. It’s especially worth noting that the group vaccinated with MMR showed no immune system memory loss after vaccination, and still gained immunity to measles.
This wasn’t just a temporary loss of antibodies after measles infection. It was as if the immune system no longer remembered that it ever encountered a particular bacteria or virus. Those immune memory cells, and the defenses they provide, were simply gone. The strong immune response against measles itself comes at the price of immune responses against other diseases.
In a separate study on unvaccinated children in the same Netherlands measles outbreak, another group of researchers led by Velislava Petrova of Cambridge, UK 4 looked at B-cell memory and function after measles infection. B-cell memory cells produce the antibodies that are used to rapidly target and destroy infectious microbes when the body encounters them. Specialized immune memory B-cells remain after infections; these particular cells disappeared during and after measles infection. Instead, the normal memory B-cells were replaced by B-cells that showed signs of immaturity and other unusual changes. Normally B-cells develop in the bone marrow, where they undergo a maturing process before heading out into the body at large. B-cells that fail to develop properly are kept from developing further and do not usually leave the bone marrow. Researchers are not sure what the post-measles-infection B-cell changes mean. However one possibility is that after measles, the bone marrow is failing to keep improperly developed cells from progressing and leaving the bone marrow. 5
The researchers also found some indications that measles may actually be infecting cells in the bone marrow and killing off the stem cells from which new B-cells develop.
Finally, what the second set of researchers found was that measles had similar effects on the immune system as a powerful antineoplastic medication, rituximab. Rituximab is used to deplete B-cells in certain cancers and in some autoimmune conditions6. The researchers wrote that this raises a concern (which has not yet been proven), that like those who take rituximab, measles survivors may actually be less effective at forming responses to microbes that they have not encountered before.
At this time, researchers are not sure if measles also causes permanent impairment to the immune system. Based on the long-term death rates after measles, they believe the immune system mostly recovers within 3 to 5 years. 1
The immune response after measles infection may be natural. But it’s not healthy or desirable.
If we define natural as “what happens without intervention”, then measles wiping out a substantial chunk of a child’s immune memory is natural. It’s as natural as gravity breaking bones when a child falls from the top of a tall playground slide. But is measles-caused immune amnesia healthier or more desirable than retaining immune memory and a functioning immune system? Is risking repeated infections and a higher chance of death for two to three-plus years truly desirable, just because it’s what naturally occurs?
In contrast, the measles vaccine gives a child life-long immunity to measles 7, while avoiding the higher risk of death and illness from measles infection. The vaccinated child gets to keep their immune memory as well. Vaccinated children don’t end up with B-cell populations that look like those receiving powerful immune-suppressing drugs. Their bone marrows are not infected with measles virus. Yes, it requires more than one measles vaccination to develop life-long immune memory against measles. Just like it takes repeated reminders, and supervision, until a child can climb to the top of the slide and go down it safely. But most parents would agree that repeated reminders and supervision are far preferable to broken bones.
Also, there is the reality that increased infections after measles means facing more, not fewer, medical interventions: more antibiotics, with all their effects on the gut biome (and increased chance of resistance). More drugs. More hospital stays. Now, some claim that measles is not dangerous to children who live in areas with good sanitation and modern living standards. However, these complications still occurred even in a study in the United Kingdom in the 1990’s through the 2000’s, with children who were well-fed and living in a developed nation. 8 For parents who want to reduce their child’s need for antibiotics and medical interventions, measles vaccine produces a better result than measles infection.
Meanwhile, rebuilding the immune system requires that the child encounter microbes and get sick again to rebuild that immune memory. In a sense, parents will have to “raise” their child’s immune system all over again, going back through the work they did in the first few years of life, when the child got sick frequently. And there is no shortcut, no diet or vitamin or herb or supplement, that will circumvent this process. Since a child who has had measles is a child who is effectively immunosuppressed, they will need to be watched more carefully than usual for signs of illness for the two to three years that this process takes. Or to put it in more familiar terms: parents, remember those preschool/early childhood years when your child was sick every time you turned around? Get ready to relive those days again.
Working together with nature to protect the immune system’s integrity
Parents, upon seeing their newborn child for the first time, often react with how perfect the newborn is. There’s a strong desire to keep them that way. When encountering claims that “natural immunity from measles infection is better than vaccination,” parents should consider which will best help their child. Giving the measles vaccination will let their child develop the same life-long immunity to measles as the infection – while keeping their immune memory, and immune system in general, whole and intact. By contrast, the measles infection, “natural” though it is, will weaken the immune system. The natural infection will require more, not less, intervention. Vaccination allows for safer development than the measles infection. To protect the integrity of the child’s immune system, parents should vaccinate against measles.
1. Mina MJ, Metcalf CJE, de Swart RL, Osterhaus ADME, Grenfell BT. Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality. Science. 2015;348(6235):694-699. doi:10.1126/science.aaa3662
2. Measles does long-term damage to immune system, studies show. CIDRAP. http://www.cidrap.umn.edu/news-perspective/2019/11/measles-does-long-term-damage-immune-system-studies-show. Accessed November 5, 2019.
3. Mina MJ, Kula T, Leng Y, et al. Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens. Science. 2019;366(6465):599-606. doi:10.1126/science.aay6485
4. Petrova VN, Sawatsky B, Han AX, et al. Incomplete genetic reconstitution of B cell pools contributes to prolonged immunosuppression after measles. Sci Immunol. 2019;4(41). doi:10.1126/sciimmunol.aay6125
5. Wesemann DR. Game of clones: How measles remodels the B cell landscape. Sci Immunol. 2019;4(41). doi:10.1126/sciimmunol.aaz4195
6. Randall KL. Rituximab in autoimmune diseases. Aust Prescr. 2016;39(4):131-134. doi:10.18773/austprescr.2016.053
7. CDC. Measles: Answers to Common Questions. Centers for Disease Control and Prevention. https://www.cdc.gov/measles/about/faqs.html. Published August 23, 2019. Accessed November 17, 2019.
8. Gadroen K, Dodd CN, Masclee GMC, et al. Impact and longevity of measles-associated immune suppression: a matched cohort study using data from the THIN general practice database in the UK. BMJ Open. 2018;8(11):e021465. doi:10.1136/bmjopen-2017-021465