Canada’s vaccine advisory committee is now recommending that those who experienced heart inflammation after their first dose of the COVID-19 vaccine should wait to get their second dose.
The National Advisory Committee on Immunization (NACI) updated its recommendations Friday, saying that individuals who experienced myocarditis and/or pericarditis after a first dose of mRNA vaccine should “wait to get their second dose until more information is available.”
Myocarditis is the inflammation of the heart muscle, while pericarditis is the inflammation of the lining around the heart.
There have been 65 cases of myocarditis/pericarditis as of June 18 in Canada out of 31.4 million vaccines administered at the time, according to federal government data.
Out of the 65 cases, 50 had the Pfizer-BioNTech COVID-19 vaccine, 10 received Moderna and five received COVISHIELD/AstraZeneca.
Among the 50 Pfizer cases, symptoms developed between five and 94 days after vaccination, 28 cases were female with a median age of 51 (age range 20 to 86) and 22 were male with an age range of 17 to 76 years and a median age of 38.
Thirty-four were after the first dose, 10 after the second and six were not specified, according to Canada’s data.
However, the U.S.’s Center for Disease Control and Prevention (CDC) found more cases of heart inflammation have occurred in males between 16-24 years old and after a second mRNA dose. NACI says that, internationally, cases are occurring more often in males under 30 years old and after a second dose.
Symptoms of myocarditis/pericarditis include chest pain, shortness of breath, or the feeling of a fast, pounding or fluttering heartbeat, and cases typically occur within a week after the receipt of an mRNA vaccine dose, according to NACI.
NACI said in a release that investigations between myocarditis and mRNA COVID-19 vaccines “continue to evolve,” and informed consent for those receiving an mRNA vaccine should include a discussion of the “very rare risk” of heart inflammation.
“NACI will continue to monitor the evidence and will update recommendations as needed,” the release stated. “The majority of cases have been mild and individuals have recovered quickly.”
An Israeli study has found there is a “probable link” between the Pfizer COVID-19 vaccine and the appearance of myocarditis among men aged 16-30. A study from the CDC came to a similar conclusion.
The new recommendation comes after Health Canada changed the product guidance for mRNA vaccines to include reports of heart inflammation, which the U.S. Food and Drug Administration (FDA) has done as well.
However, Canada’s Chief Public Health Officer Theresa Tam said in a statement Friday that the benefits of mRNA COVID-19 vaccines continue to outweigh their risks.
“It is important that everyone gets their second vaccine dose to provide the best protection.”
-With files from Global News’ Saba Aziz and Reuters