Editor's Note: (Robert Klitzman is a professor of psychiatry and director of the masters in bioethics program at Columbia University. He is author of "Designing Babies: How Technology is Changing the Ways We Create Children." The opinions expressed in this commentary are solely those of the author. View more opinion articles on CNN.)
(CNN) "Should I get a Covid booster shot?" a friend recently asked me. He's 50 years old and in good health.
I told him that the data didn't indicate that he needed one -- yet.
"But I want one anyway -- just to be safe," he said.
He is hardly alone. Understandably, many people are afraid of the ongoing Covid-19 pandemic that has again surged across the country due to the highly contagious Delta variant and because about a third of eligible people in the United States have not received even one dose of a vaccine. Yet, over 1 million Americans have received a booster shot, according to ABC News. Still, complex medical and ethical issues are involved.
The US Food and Drug Administration is expected to announce this week that it is authorizing the use of additional Covid-19 doses for some people who are immunocompromised, according to a source familiar with the discussions.
Recent data shows that, overall, current vaccines are extremely effective against the Delta variant. The Pfizer-BioNTech vaccine is 93.7% effective against the Alpha variant, 88% effective against the Delta variant and 96% effective against severe disease from Delta. The Moderna vaccine is 72% effective against Delta and even one dose is 96% effective against severe disease from Delta. And the one-dose Johnson and Johnson shot is 85% effective against severe disease from Delta.
In comparison, flu shots are only 40% to 60% effective.
Still, individuals vary. In particular, people who are immunocompromised or have certain medical problems or are elderly have increased risks of getting severely ill if they become infected. A recent Johns Hopkins study found that vaccinated immunocompromised people are far more likely to end up in the hospital or die from Covid-19 compared to the general population that is vaccinated.
However, more data is needed to show the need for boosters for everyone.
Data from the Ministry of Health in Israel suggests that people who got vaccinated earlier in the past year were more likely to later test positive for the virus than were people vaccinated more recently. But the data has sparked controversy, since individuals may test positive but not get serious symptoms. In addition, people who tested earlier were more likely to be either health care workers, who are at higher risk of viral exposure, or wealthier and able to travel abroad, requiring that they undergo tests. The data, thus, appears to have biases.
Moreover, most of the world still lacks vaccines. That's why, last week, the World Health Organization called for a moratorium on distributing booster shots until at least the end of September. WHO Director-General Tedros Adhanom Ghebreyesus reported that 80% of the supply is going to countries with less than half of the world's population. Whereas most people in certain countries have been fully vaccinated (including 72.5% in the United Arab Emirates, 62.5% in Canada and almost 50% in the US), less than 1% have been in 22 countries. While logistical difficulties have hampered the rollout in some countries, for much of the world inadequate supplies of vaccines remain the key problem.
Ultimately, if everyone in the US and other wealthy countries who wanted a booster got one, far fewer doses would be available for the rest of the world.
Some people may dismiss these poorer countries' needs. But Covid is showing us how, in both getting the virus and preventing it, we are all tightly interconnected.
In our globalized economy, countries have generally failed painfully in sealing their borders. No wall has stopped this airborne microbe. The more people are unvaccinated around the world, the more likely it is that highly resistant variants will emerge and appear here. Hence the belief that low vaccination rates in other countries don't affect us is false.
Vaccine manufacturers are now emphasizing the need for boosters but are also not unbiased. They have made billions of dollars in profit. If people get boosters, they would likely make billions more. Last month, Pfizer released new data suggesting that a third dose of its vaccine can increase blood antibody levels against the Delta variant, but the data, and the details involved, has not yet been published, and whether boosters will reduce risks of symptoms remains uncertain.
Clearly, the pandemic is a moving target. Additional data may indicate that vaccine effectiveness drops significantly over time such that more symptoms occur, or new, more resistant variants may surface.
Yet for now, given the lack of clear benefit, and the potential harms, people without weakened immune systems should proceed with caution. In the end, such caution can help us all.