Measles is not a harmless childhood infection – Dr. Bowdish explains.

See Dr. Bowdish’s op-ed piece in the Globe & Mail.

The G&M article is paywalled so you can also read the text below with some additional links to relevant publications:

Dr. Dawn Bowdish is the executive director of the Firestone Institute for Respiratory Health, the Canada Research Chair in Aging and Immunity, and a professor of medicine at McMaster University.

Measles infections are on the rise, particularly in Europe and the U.S., while vaccination rates have declined – but too many have dismissed these trends, seeing measles as just a harmless childhood infection. But it is, in fact, the cause of the most deaths of all the vaccine-preventable infections. Canadian deaths from measles may be rare due to excellent medical care, but measles can have long-term consequences that are worth avoiding.

Before antibiotics were available, measles killed more people than influenza. When a child develops the high fever and rash characteristic of measles, the virus infects and destroys white blood cells, specifically those called lymphocytes. This leads to a period of immune-system suppression, where bacteria that normally live on and inside us without serious issue can cause deadly pneumonia or other infections.

With antibiotics, we can help children through this risky period, although the rise of antibiotic-resistant bacteria means that we can’t be as confident as we once were. What we can’t fix, however, is the damage that measles does to lymphocytes.

Our lymphocytes are essential to the generation of immune responses to new infections and vaccinations, but also in the system’s ability to “remember” the immune responses we’ve already generated. Measles infects and kills these critical immune cells. As a result, we know that a child who contracts measles will probably have more infections and more antibiotic prescriptions for at least five years after their infection, likely because they are getting sick with things that they once had immune protection from. We also know that even as their lymphocyte numbers recover, some are lost and the quality of others are reduced. This is why deaths from many unrelated infections also decreased when the measles vaccines were rolled out; measles no longer caused those children to “forget” their learned immune response.

Measles during pregnancy is dangerous. Miscarriage, premature labour, congenital birth defects, neurodevelopment disorders, or even the death of both mother and baby are all very real possibilities. In some parts of the world, when a woman plans to get pregnant and there is any doubt about her vaccine status, her healthcare provider will test for antibodies to make sure she is protected or recommend vaccination. In Canada, however, this is rare. Pregnant women are often not against being vaccinated, but often feel that not getting vaccinated is safer than getting vaccinated. This, compounded by a well-organized and concerted misinformation campaign about the measles vaccine that began in the 1990s, means that many people born in this era are now entering their child-bearing years having never received their childhood vaccines.

Measles is the most infectious virus we know of, and the increasing number of measles infections locally and globally mean that we can expect to see its tragic effects in pregnancy once again. Midwives, family doctors, and caregivers need to recommend vaccination for measles and other vaccine-preventable infections in the strongest possible terms.

There are some “known unknowns” that make the recent measles outbreaks particularly worrisome. We don’t know whether measles-induced immune suppression will make COVID, respiratory syncytial virus (RSV), streptococcal infections and other surging issues worse. We don’t know what proportion of Canadians have waning measles immunity and whether this means we need booster campaigns. We don’t know if people on immunosuppressant drugs or chemotherapy have lost their protective measles immunity, and if they have, we don’t know if our long-term care homes and cancer centres are at risk of outbreaks – though we do know that our strained healthcare and public health systems are under-resourced and will struggle to cope.

Misinformation, pandemic-related gaps in vaccine delivery, and the continuing countrywide shortages of family doctors means that many Canadians have not been vaccinated. But it’s not too late. The National Advisory Council on Immunization has clear guidance on how people of any age can catch up on their vaccines. If you have any doubt as to whether you were vaccinated, especially if you are thinking about becoming pregnant, speak to your health care provider or public health unit. Even if it turns out you were vaccinated and didn’t know it, there is no safety concern around getting vaccinated again. Children can also be vaccinated if they’ve missed their vaccines for any reason. And we should continue to enforce existing rules that require vaccines to go to school and work in certain sectors.

The terrible consequences of measles in pregnancy and childhood were known to our grandparents and great-grandparents. They are not a lesson that any of us need to learn again.

See also:

SARS-CoV-2 and Back to School (Part 1)


If children can catch SARS-CoV-2/COVID-19 and carry as much of the virus, why are we considering opening schools? In part 1 Dr. Bowdish discusses how the virus spreads and why this might be different between children and adults. (Short answer= children spread less because they are more likely to be asymptomatic and less likely to cough/sneeze when they are infected than adults.) Topics covered in this presentation include: 1) Which countries have successfully opened schools and why? 2) Why droplet size matters? Coughs and sneezes spread more than talking/breathing. 3) Symptoms that differ between adults and kids. 4) Priority #1 for keeping schools safe – keep people with symptoms, no matter how mild out.

To download the slides used in this talk see click here. If you would like the video in another format (e.g. .mp4, .wmv) please email Dr. Bowdish at

Bowdish Lab Hosts Future Female Scientists (Canadian Association of Girls in Science).

On Thursday March 7th, the Bowdish Lab welcomed a group of five to twelve year old girls for a night for a night of science fun! In association with The Canadian Association for Girls In Science (CAGIS), the Bowdish lab opened its doors to promote and encourage our future young scientists.

CAGIS is an award winning national science club for girls aged 7-16, the purpose of which is to promote, educate and support interest and confidence in science, technology, engineering and mathematics among girls. Needless to say, The Bowdish Lab jumped at an opportunity to inspire such an eager group.

The night began with an introductory presentation by Dr. Bowdish which introduced theDawn gives out cards girls to basic concepts of immunology, good and bad germs and the members of the Bowdish Lab. Dr. Bowdish proposed a challenge to the girls; to encourage scientific inquiry, whoever asks the greatest number of scientific questions by the end of the night will win a prize! Every time a student asked a question, they would receive an official Dr. Dawn Bowdish business card to keep track. Dr. Bowdish nearly ran out of business cards IMG_0796 - Copybefore the end of the presentation!


The girls were then split into groups of two to three to take part in a variety of hands-on scientific activities. Of course, if the girls wanted to participate in awesome science activities, they need the proper scientific attire.






Girl & microscope


Members of the Bowdish lab organized five stations to help explain what we do as scientists. . Mike Dorrington introduced the girls to using a microscope to analyze anything from blood to nasal wash samples. Mike showed the girls how we separate blood into different components in order to isolate white blood cells. The girls were then able to observe the various types of white blood cells using pre-prepared slides. Bowdish lab organized five stations to help explain what we do as


Alicja & student

Alicja Puchta demonstrated how scientists develop special film to analyze anything from X-ray results to protein analysis. The girls were taken into a totally different world – the dark room. Special red lights allow for scientists to avoid exposing sensitive film to normal light. The girls were able to expose film to a variety of objects such as CD’s and pens and develop the film for their own take-home souvenir!

Avee Naidoo and Keith Lee introduced the concepts of acid and base chemistry using aColoured bubbles red-cabbage based pH indicator. The girls were allowed to use common household products to visualize changes in pH. Acids like vinegar turned the purple solution a bright neon pink, whereas bases such as baking soda turned the solution to blue and green. The grand finale was to add a piece of dry ice into a (green) basic solution. What would happen? The dry ice was able to turn the solution a variety of colors from green to blue to purple to pink in an eye catching manner.

Kyle Novakowski explained the concepts of dry ice and how we as scientists rely on it to send samples around the world while keeping them very cold. Students were shown what happens when dry ice is added to warm water and the process of sublimation. The resulting CO2 gas was then bubbled through a soapy solution to make spooky “boo bubbles” which the girls were able to hold in their very own hands. The girls were very excited to pop the bubbles and witness the escaping gas.

C02 is fun

Although the girls did not wish to be whisked away from the exciting applic

Pretty plates

ation s of dry ice, Dr. Preethi Jayanth was able to maintain the same level of fun at her stations. Our future scientist guests were able to observe various types of agar used to grow

After a few hours of exciting science, our champion question-asker was awarded a prize during a wrap-up Q&A session with Dr. Bowdish and the lab members. The immense amount of positive feedback and enthusiasm made for a wonderful night that we hope to experience again soon.bacteria. While peach and chocolate agar may sound appetizing – nobody would want to eat this stuff! The girls were given the opportunity to detect microbes on their own hands before and after washing! Two to three days later, the girls were sent pictures of all the bacteria on their hands which had grown on the agar.

Scientists plus girls excited about science