This article is part of the Harvard Medical School. continuous coverage of medicine, biomedical research, medical education, and policies related to the SARS-CoV-2 pandemic and COVID-19 disease.
Blood type is not associated with a severe worsening of symptoms in people who tested positive for COVID-19, report researchers at the Harvard Medical School based at Massachusetts General Hospital.
Their findings, published in the Annals of hematology, dispel previous reports that suggested a correlation between certain blood types and COVID-19.
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However, the study found that symptomatic people with blood types B and AB who were Rh positive were more likely to test positive for COVID-19, while those with blood type O were less likely to test positive.
“We showed through a multi-agency study that there is no reason to believe that a certain type of ABO blood will lead to increased disease severity, which we define as requiring intubation or leading to death,” said the study’s lead author. Anahita Dua, Assistant Professor of Surgery at HMS at Mass General.
“This evidence should help end previous reports of a possible association between blood type A and an increased risk of COVID-19 infection and mortality,” said Dua.
The increase in COVID-19 in all corners of the world sent scientists to look for characteristics that could make people more susceptible to the virus, as well as risk factors that could intensify its severity and progression.
This has spawned numerous theories and reports about the association between COVID-19 and blood type, which have often generated more questions than answers.
HMS researchers at Mass General launched their own investigation by turning to the massive database of the Research Patient Data Registry of the Mass General Brigham Health system.
A study population of 1,289 symptomatic adult patients, who tested positive for COVID-19 and had their blood group documented, were selected from more than 7,600 symptomatic patients at five Boston-area hospitals, including Mass General and Brigham and Women’s Hospital, treated from March 6 to April 16 of this year.
Without connection
Statistical analysis determined the independent effect of blood type on intubation and / or death of these infected patients.
The large retrospective review did not show a significant connection between blood type and worsening disease, between blood type and need for hospitalization, positioning requirements of patients during intubation, or any inflammatory markers.
“Inflammation is a particularly important finding because the prevailing scientific thinking is that COVID-19 wreaks havoc on the body through systemic inflammation, which can lead to morbidity and death,” said Dua. “However, we found that the inflammatory markers remained similar in infected patients, regardless of their blood type.”
An intriguing finding from the study was that there appeared to be a greater chance that people with blood types B and AB who were Rh positive tested positive for the virus. Even the team gathered stronger evidence that symptomatic people with blood type O were less likely to test positive.
“These findings need to be further explored to determine if there is something inherent in these blood types that could confer protection or induce risks in people,” said Dua.
For now, however, the researchers are confident that their main finding, that ABO blood typing should not be considered prognostic in patients acquiring COVID-19, will help to discredit the types of clinically unfounded rumors and disinformation that can easily gain traction in the in the middle of a pandemic, and in some cases they become part of accepted medical practice.
Adapted from a Mass General press release.
Image: Getty Images
