Experts skeptical of study linking blood type to COVID-19 risk
TORONTO -- Facing a growing pandemic, the medical research community has quickly mobilized to study every inch of the novel coronavirus responsible for COVID-19.
Headlines touting new discoveries about the deadly disease, responsible for more than 500,000 cases worldwide, have begun spreading rapidly on social media.
But not all studies are created equal.
A study conducted by a group of Chinese researchers claiming that people with type A blood may be more susceptible to contracting COVID-19 is the most recent example of these viral studies.
The research, which has been picked up by mainstream media outlets and shared widely on social media, analyzed 2,173 patients who contracted the COVID-19 virus from three hospitals in Wuhan and Shenzhen, China.
Scientists looked at the distribution of blood types in the normal population of each area, and then compared it to their COVID-19 patient sample. According to the findings, those with type A blood “had a significantly higher risk for COVID-19 compared with non-A blood groups.”
Although the study itself is real, experts warn its findings are extremely preliminary.
Worse yet, the study was not validated by peer review, a process reputable scientific journals use to check the validity and biases of a study before publishing them.
The study was made public on medRxiv, a website where researchers can post "complete but unpublished" medical research to generate debate among experts.
“I think the study is interesting, but it’s quite early days… and it’s not been through proper scientific peer review,” Dana Devine, chief medical and scientific officer at Canadian Blood Services, told CTVNews.ca by phone Wednesday.
“I’m a bit skeptical.”
Devine, an expert in blood pathology, notes that there are some blood group associations with certain kinds of diseases, such as the ability of malaria parasites to get inside of red blood cells.
“The concept that blood antigens could be associated with something is not completely off the wall,” she noted.
“But this study particularly really needs to be looked at in a larger population with a more critical analysis than what these folks have managed to do so far.”
Devine notes that blood still plays an important role in any emergent health care situation. Canadian Blood Services is still asking Canadians to donate blood to help bolster supplies as the pandemic takes shape in Canada.
“We want Canadians to understand that we have our blood clinics set up in a way where we are responding to an essential service need for hospitals. People still need blood,” she added.
“We have put in place physical distancing practices at the clinics. We’re very conscious about not exposing donors to any risk. It’s a safe place to go.”
WHAT MAKES A REPUTABLE STUDY?
Experts say there’s no question that preliminary research plays an important role in developing a solution to the COVID-19 pandemic, whether it be through the development of a vaccine or better screening measures.
But the average person should be especially careful when giving any weight to these studies, especially before sharing them on social media.
“I would recommend focusing on reputable sources,” Dr. Craig Jenne, researcher and infectious disease specialist with the Cumming School of Medicine at the University of Calgary.
“If there is a new drug, a new discovery, or a cure and the World Health Organization (WHO), Public Health Canada, or the CDC [U.S. Center for Disease Control and Prevention] has not commented on it, I think you have to evaluate those other articles with a grain of salt—or at least an air of skepticism.”
Jenne, who serves on the review board for two scientific journals, notes that there has been a recent uptick in non-peer reviewed journals or websites where scientists can post their work directly.
He explains that peer reviewed journals undergo rigorous controls and fact checking by scientists in similar fields to double-check statistics, ensure there were proper controls in the study, and that the authors had all of the experimental parameters to allow them to interpret the results fairly.
“Often times there are minor problems and it has to go back to the original author to do additional experiments to verify the results,” he said.
But Jenne says although studies that don’t undergo these stringent peer review measures are “problematic,” it doesn’t necessarily mean they are incorrect.
“Just because something isn’t peer reviewed doesn’t mean it’s wrong. It just means it hasn’t been checked yet,” he said.
“Without having a proper study conducted, one that passes peer review, it’s really hard to say whether what the scientists or the authors observed is real.
I’m not saying that they’re faking data. I think we have to be very careful that unless a study is conducted properly you may be getting a result that’s not reflective of the whole population.”
Jenne notes that in the case of emergent viruses, like COVID-19, peer review journals have an expedited review process that allows them to publish new findings as soon as possible. However, those studies still undergo this rigorous blind peer review process.