3 minute read
variant may ‘break through’ pfizer vaccine, study says
the south african variant is believed to be 60 per cent more transmissible than the original strain.
opinion: weighing the risks, benefits of covid vaccines
canada's messaging about vaccinations has to be clearer than it was with the astrazeneca vaccines, writes dr. harry rakowski.
a nurse from humber river hospital administers the pfizer/biontech covid-19 vaccine at st fidelis parish in toronto, ontario, canada march 17, 2021.
carlos osorio
/
reuters
while concern continues to grow around the possible link between the mrna vaccines and inflammation of the heart muscle (myocarditis) and its pericardial lining (pericarditis) — particularly in young people — there are key issues that need to be understood in order to properly determine risk.
flu can affect the heart too
many non-covid viral infections causing annual flu have a low risk of associated myocarditis or pericarditis, but often this complication is mild and resolves without permanent heart damage. however, rarely, it is life threatening if there is a severely weakened heart muscle.
many non-covid viral infections causing annual flu have a low risk of associated myocarditis or pericarditis, but often this complication is mild and resolves without permanent heart damage. however, rarely, it is life threatening if there is a severely weakened heart muscle.
clearly, the sars co-v-2 virus causing covid-19 is more dangerous than simple influenza, so it’s not a surprise that infection with the virus has a much higher risk of heart complications. and while we know that cases of heart muscle damage have occurred, the incidence is unclear, mostly because it depends on how the diagnosis is made.
how are we keeping track?
early reports from the israel health ministry, where most residents were vaccinated with the pfizer mrna vaccine, raised an initial signal that vaccination might be associated with myocarditis or pericarditis and needed closer observation.
related stories
advertisement
the fda and cdc track post vaccination reports of possible side effects through vaccine adverse events reporting system (vaers). they then compare reported adverse event rates to the expected rates that typically occur without vaccination and determine whether there is an excess of occurrences. if so, an association is reported, a cause is attempted to be found and a decision is made on risk-benefit to guide decision making.
reported u.s. incidence
the may 31, 2021 u.s. data as reported by the cdc showed that of the many millions of doses given, almost 800 cases of these heart events were reported within 30 days of second vaccination. event rates remain very low in the many tens of millions of people vaccinated. however, the rates are not uniform. in men under 25, 277 cases were reported, and while this group represented 8.8 per cent of those vaccinated, they accounted for 52 per cent of total reports. while most people recover, about 10% have more serious disease with rare deaths.
the may 31, 2021 u.s. data as reported by the cdc showed that of the many millions of doses given, almost 800 cases of these heart events were reported within 30 days of second vaccination. event rates remain very low in the many tens of millions of people vaccinated. however, the rates are not uniform. in men under 25, 277 cases were reported, and while this group represented 8.8 per cent of those vaccinated, they accounted for 52 per cent of total reports. while most people recover, about 10% have more serious disease with rare deaths.
when does it occur?
according to the cdc, most reports come within a few days after the second dose rather than the low risk associated with the first dose. reported cases are much more frequent in men than women.
according to the cdc, most reports come within a few days after the second dose rather than the low risk associated with the first dose. reported cases are much more frequent in men than women.
advertisement
what does this mean?
current guidelines strongly recommend vaccination for everyone 12 and older. while the 12-25 year old groups have low complication rates from infection, serious disability and death may still occur. at the same time, this age group also may be a repository for infection that could accelerate a fourth wave due to increased risk of the delta variant. it is for this reason that the threshold for vaccination safety be set higher.
current guidelines strongly recommend vaccination for everyone 12 and older. while the 12-25 year old groups have low complication rates from infection, serious disability and death may still occur. at the same time, this age group also may be a repository for infection that could accelerate a fourth wave due to increased risk of the delta variant. it is for this reason that the threshold for vaccination safety be set higher.
vaccinations to date have been very safe despite adverse events
the cdc and the american heart association continue to advise that vaccination should continue for all age groups, stating that the benefit to both individuals and society is greater than the small risks of potential complications.
the cdc and the american heart association continue to advise that vaccination should continue for all age groups, stating that the benefit to both individuals and society is greater than the small risks of potential complications.
should we pause vaccinating the under-25s?
it may be reasonable to take a two week pause in vaccinating men under 25-years-old with a second dose, while we better understand the data around adverse events and determine true risk. this review is currently underway by u.s. regulators — we need to be reassured that any risk is being carefully reviewed and neither minimized nor exaggerated.
it may be reasonable to take a two week pause in vaccinating men under 25-years-old with a second dose, while we better understand the data around adverse events and determine true risk. this review is currently underway by u.s. regulators — we need to be reassured that any risk is being carefully reviewed and neither minimized nor exaggerated.
we also need to have trust that decisions are being made wisely based on scientific data and options, and then tailored appropriately to canada’s situation. more second shots in arms are needed to better protect against the more dangerous delta variant — one dose is just over 30 per cent protective against it, while second shots are 88 per cent protective.
advertisement
let’s clear up our messaging
canadian messaging about next steps in terms of vaccines has to be much clearer than what happened with the astra zeneca fiasco — az vaccination was halted in many countries due to rare clotting complications with poor communication around the risks versus the benefits. while it’s important we don’t minimize risk to facilitate vaccination, at the same time, we can’t let vaccine deniers use this very small risk to further the unfounded conspiracy theory that vaccines are highly dangerous.
canadian messaging about next steps in terms of vaccines has to be much clearer than what happened with the astra zeneca fiasco — az vaccination was halted in many countries due to rare clotting complications with poor communication around the risks versus the benefits. while it’s important we don’t minimize risk to facilitate vaccination, at the same time, we can’t let vaccine deniers use this very small risk to further the unfounded conspiracy theory that vaccines are highly dangerous.
poet robert frost said that “freedom comes from being bold.” we can be both bold and wisely careful in fighting this pandemic.
dr. harry rakowski is a toronto-based academic cardiologist.
share story
