The controversy over vaccination and boosters continues to rage. Recent guidance by Florida’s Surgeon General, Dr. Joseph Lapado, recommends that men aged 18-39 not get the new bivalent mRNA boosters. This is based on local data suggesting that there is an increased risk of cardiac death in this population which outweighs the possible benefit.
This decision required a careful analysis of whether there is data that may support such an opinion. Rather, it received immediate censure from those very much in favour of vaccination. Dr. Lapado’s tweets were also taken down by Twitter (although the decision was quickly reversed). Any concerning reports about vaccine safety require serious review, not knee-jerk reaction, even if believed to be politically motivated.
Let’s review what we know
Original vaccines and boosters now protect mainly from hospitalization and death rather than infection itself.
Most of the North American population has experienced infection regardless of vaccination status. Most infections have occurred with a less severe Omicron variant, and currently almost all are due to the BA.4 or BA.5 variant.
Newer bivalent boosters were developed to try and prevent infection from these evolved Omicron variants. Unlike the original vaccines, which had a 95 percent benefit in preventing infection, very little human data is available about the efficacy of bivalent boosters. There is a reasonable presumption based on animal and lab studies that they will be protective from infection. Their safety is also based on a reasonable presumption that their small risks will be similar to those documented in the very large number of very similar mRNA vaccines already administered.
Benefits and risks of vaccination vary with age
Very few people ages 18-40 have died of COVID-19 throughout the pandemic, even prior to the availability of vaccines. Canada has reported about 480 deaths in people aged 20-39 from the start of the pandemic until November 7 of this year, compared to about 47,000 total deaths. Thus the 20-39 age group represents only about one percent of all COVID-19 deaths.
The rate of death in this young age group is historically extremely low and even lower now with less severe disease from Omicron variants. Most people have protection from serious outcomes by a combination of primary vaccination or previous infection. Even the unvaccinated face lower risks from the Omicron variants than during Delta, which was primarily a disease of the unvaccinated.
Myocarditis is a relatively rare but real potential complication of mRNA vaccination, occurring in about 1/10,000 people, most of whom recover fully. This complication occurs much more frequently in people under the age of 40, especially young men. A population-based study published in JAMA on June 24, 2022, looked at reported myocarditis complications in an Ontario population of 14.5 million people who received 19.7 million doses of mRNA vaccines between December 2020 and September 2021. Surveillance was greater after June 2021 so earlier cases may have been undercounted. There were 297 reports of myocarditis or pericarditis from either the vaccine registry or passive surveillance.
The risk was highest in men (76.8 percent) and especially after the second dose (69.7 percent). Indeed the risk for men in the 18-24 year age group was about 3/10,000. This analysis may be an underestimate of risk since it is likely that mild cases were not tracked or reported. We don’t yet know if a third or fourth booster dose further increases the risk.
While most people who develop myocarditis do well and death is rare, it remains a complication of concern. Sudden cardiac death in the young can occur with even mild myocarditis. There are reports of significantly increased rates of sudden death in athletes in 2021, the year vaccination was introduced. Some of these deaths may be due to clinical or silent vaccine-related myocarditis. It is, however, likely that most of these deaths were related to complications of increasing rates of infection by more serious variants since infection has a much higher risk of causing myocarditis than vaccination itself.
The Florida Department of Health study that Dr. Lapado based his recommendation on, showed an apparent 84 percent increase in cardiac-related deaths in young men 18-39, within 28 days of becoming vaccinated with mRNA vaccines. Many epidemiologists have challenged the findings based on flawed methodology and data analysis in a report that has not undergone the critique of peer review required of high-level scientific studies. A key omission was the lack of a comparison group for rates of cardiac death in those who became infected without being vaccinated.
Analysis of the benefits of vaccination and the risk of infection has been plagued by junk science and political science both by proponents and opponents of vaccination. Just because Dr. Lapado and Governor DeSantis are against vaccination in younger adults, or you may not like their politics, it doesn’t mean their concerns should automatically be discounted.
Their data needs more critical assessment and publication in a peer-reviewed journal. We also need to analyze cardiac deaths in younger adults more carefully in other jurisdictions to see if there is a worrisome trend.
The current focus of giving bivalent boosters should be for people aged 50 and older and those with other important risk factors for poorer outcomes. Younger people who currently are at low risk may make their decision about further vaccination based either on the faith that it is personally beneficial, or will prevent cross-infecting those at higher risk. Many may choose to wait while the disease burden is low for clearer clarification of risk versus benefit. They shouldn’t be shamed or shunned for exercising their rights. However, they should also be influenced by quality science, not disinformation.
