“Frankly, I’m worried,” says immunologist Samira Jeimy of the increasingly widespread measles outbreaks worldwide and local outbreaks on the rise here in Canada.
Though the horrors of measles are too far back for many in North America to remember, there was a time when measles decimated entire populations. With measles making a comeback and vaccination rates that haven’t kept up, what can we expect as the virus continues to spread?
Healthy Debate sat down with Jeimy to learn more about measles and the bizarre and horrifying toll it can take on our bodies and communities. This interview has been edited for length and clarity.
To start off, what exactly is measles?
Measles is an RNA virus and one of the most contagious of known diseases. Measles infections were once one of the leading causes of mortality and morbidity worldwide. After the vaccine was created, it was declared eliminated in the United States in the early 2000s as there wasn’t disease transmission in the country for about a year.
But after the measles, mumps, rubella (MMR) vaccine and autism myth perpetuated based on a publication that was later redacted for falsifying data, measles immunization rates have declined in North America. Before, we would have occasional imported disease but now we are hearing about many non-travel associated outbreaks in North America and across Canada.
The incubation period is about two weeks, so a person could be asymptomatic and shed viral particles during that period. Younger children, especially unvaccinated younger children, and pregnant women are exceptionally susceptible to serious side effects and even mortality.
What are the symptoms of the measles?
Classic symptoms are cough, a runny nose, conjunctivitis, a flat red rash that may involve all the skin of the body, and Koplik spots, which are white spots that appear in the mucous membranes of the mouth.
More serious side effects include pneumonia, either from the measles virus itself or a secondary bacterial pneumonia. Secondary complications like ear infections and gastrointestinal illnesses are also common. Some patients get keratoconjunctivitis, a more severe form of conjunctivitis that can lead to blindness.
Measles can cause neurologic complications including encephalitis, as well as various demyelinating diseases that can cause widespread inflammation in the brain and spinal cord and can be fatal. Children under two may develop seizures from measles infection, which can affect their brain to the point they have impaired cognition and motor skills.
These diseases may not immediately appear but can emerge years after the initial infection.
What happens to the immune system of someone who has not been vaccinated against measles?
Measles can cause something called “immune amnesia,” in which the virus wipes out existing antibodies for other viral and bacterial infections that that person was exposed to during their lifetime. Antibodies are vital proteins that protect you by binding to unwanted pathogens, like bacteria, viruses, fungi, etc., to destroy them. Our immune system relies on a memory response through antibodies to properly identify and attack unwanted pathogens. But the measles virus will bind to those antibodies and destroy them, clearing out anywhere from 10 to 70 per cent of existing antibodies.
By neutralizing these protective antibodies, measles takes your immune system back to a state where it thinks it’s never fought off an infection before – and remember, it’s not just infections, it’s also vaccines. In immunology, we refer to this as a secondary immunodeficiency.
When the measles virus attacks our antibodies, how long do we have to live with this secondary immunodeficiency?
This is a fairly long-lasting phenomenon. The secondary immunodeficiency usually lasts up to a year before your immune system will learn how to “remember” new pathogens again. Some studies have found effects lasting up to three years in children.
After a few years, your immune system will likely regain the ability to recognize and protect itself from new infections. But there’s no predicting which infections your body will have forgotten so you’d have to get all your routine immunizations again.
How can you tell if you’re experiencing immune amnesia from measles?
Typically, secondary immune deficiencies declare themselves when a person keeps getting sick repeatedly, or with unusual organisms in unusual patterns. The infections are often complicated by more severe health outcomes.
If you have a kid in daycare or in school, they may experience being sick all the time to the point where they fail to thrive. They’ll also become repeatedly sick requiring hospitalization or multiple rounds of antibiotics.
Measles takes your immune system back to a state where it thinks it’s never fought off an infection before.
How protected are we by vaccination?
The measles vaccine is quite interesting. If you were born before the 1970s, measles was so contagious that you are just presumed to be immune from natural exposure. A lot of people born before 1970 are not actually vaccinated, but we don’t know what their level of protection is.
If you were born after 1970, up until the 1990s, you only received one vaccine, which is about 90 per cent effective. After that, a two-dose series was then considered a complete series, which is 97 per cent effective in decreasing transmission. If you aren’t sure if you’ve been vaccinated, talk to your doctor. There is no harm in getting vaccinated against measles again to be sure you’re covered.
If you have been sufficiently vaccinated, are you still able to get sick with the measles or would your symptoms just be milder?
You’re not likely to get sick at all due to the high effectiveness rate. There is, however, some waning of vaccine-related immunity.
The measles vaccine is incredibly effective at generating an antibody response because it is a live-attenuated vaccine. That’s also why we don’t give it to our immunodeficient patients – because they will be at risk of actual measles and its complications from the vaccine.
What is a live-attenuated vaccine?
A live-attenuated vaccine means that the vaccine contains a weakened version of the virus that causes the disease. These types of vaccines can be dangerous for people with specific types of immunosuppression because they don’t have the immune capacity to mount a good enough response to manage even a very weak form of the virus.
But it’s perfectly safe for people without immunodeficiencies. This is also why it’s important for healthy people to get vaccinated to prevent spreading measles to people who are unable to be vaccinated for medical reasons.
The evidence suggests that COVID-19 can damage immune systems. Given this resurgence of measles outbreaks, how might this impact a population that’s likely had repeated COVID infections?
There’s a huge amount of evidence that supports that COVID-19 infections cause immune dysregulation, even (for) those with quite mild infections. We’ve seen unusually high rates of RSV, invasive strep bacteria, and walking pneumonia recently. We’re also seeing a number of unprecedented outcomes from infections that we don’t normally see. In my clinic, there’s been an increase in things like hives and rashes triggered from exposure to cold temperatures.
There’s no way for me to say for sure that there’s more strep because of immune dysregulation from COVID, but something is definitely different now. This makes me all the more concerned about the possibility for more severe infections with these measles outbreaks.
Should people with Long COVID be concerned about getting vaccinated with a live-attenuated measles vaccine?
Although there’s a lot of evidence for a connection between immune dysregulation and Long COVID, it doesn’t seem to have caused an immune deficiency to the point where we’re recommending that these patients need to avoid live virus vaccines.
Why is vaccination superior to natural infection in this case?
If you have a natural infection, are you possibly going to have lots of antibodies produced? Yes. But what about the potential consequences of uncontrolled infection? All those secondary infections that we talked about – the brain complications and immune amnesia – those are the risks we’re taking a chance on with natural infection. There’s no way to predict who will have an adverse outcome from infection. It’s just taking a shot in the dark on something that’s long lasting and damaging.
There’s a lot of benefits to vaccination on a population level. One research paper showed that having a population highly vaccinated against the measles cut mortality from all forms of non-measles infection in half. That’s pretty incredible.
This is likely due to the increased susceptibility to other serious illnesses that results from the damage measles can do to the immune system. Before a vaccine was developed, 2.6 million people a year were killed by measles. It’s really not trivial. 20 per cent of people in North America that have natural infections end up being hospitalized, predominantly with complications like pneumonia and encephalitis. The infection is especially damaging in pregnant people.
Why is it so severe in pregnant people?
In pregnancy, the immune system undergoes some pretty profound changes so that you can tolerate foreign genetic material. This causes a lot of immune system changes, particularly in something called cell-mediated immunity, or the part of your immune system that takes a lead role in fighting viral infections.
We previously had such good vaccination rates that we weren’t as concerned about measles and pregnancy compared with other diseases. But now with higher rates of measles, we’re seeing an increase in premature labour, low birth weight and miscarriage. It’s quite significant. It’s reached the point where it’s standard to do measles antibody level checks as part of routine checkups in pregnancy.
When it comes to Canada, on a population level, how concerning is this rise of measles outbreaks?
Honestly, it’s a bit of a disaster. The lessons we learned from COVID is that trust in our health-care system is at an all-time low. Disinformation is everywhere, and often packaged in a far more attractive way than the scientific evidence that refutes it.
The myth about the MMR autism paper will not just be put to rest despite mountains of evidence to the contrary, including the retraction of that original paper. There’s an expression that a lie will make it around the world 18 times before the truth does. With all the antivax activity around the COVID vaccine, we have seen people continue to peddle myths like the autism theory and broaden it to apply to multiple routine immunizations.
A lot of the rise in antivax activity is due to the privilege of never having to see the horrendous outcomes of many of these preventable illnesses. The pendulum has swung so far because the horrors of widespread measles outbreaks are too abstract a concept for most people in North America to grasp.
Instead, they’ll attribute the vaccines to other childhood diagnoses like autism, which frankly, there’s multiple reasons why that’s offensive. But I think that first paper on autism and MMR in the 1990s was a big driver of something that’s really snowballed.
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