Eight people who work for the New York Yankees baseball team, including a player, tested positive for Covid-19 – and all of them were vaccinated against the virus just over a month ago.
It sounds bad. But don’t panic. (Or, if you’re a Red Sox fan, stop smiling.) These “groundbreaking” cases don’t mean vaccines don’t work, or that a vicious new vaccine-proof variant has spread to through the Yankees. cloakroom. They do mean, however, that it might be a bit early to take those masks off.
Manager Aaron Boone on Wednesday announced seven cases among team staff; The Yankees also put the shortstop Gleyber Torres on Thursday on the Covid-19 injured list– he had the disease in December, was vaccinated and tested positive again. Fortunately, six of the staff’s seven cases were asymptomatic. The reason anyone has found out is that the team regularly tests staff and players.
It’s the curved ball here. “Groundbreaking cases are underreported because many will be asymptomatic,” says Ana Isabel Bento, disease ecologist at Indiana University’s School of Public Health. “And most people won’t get tested unless they have to, or they experience symptoms.”
So it’s impossible to say how weird this team epidemic really is, as no one knows the denominator – the number of people who, after being vaccinated, are still infected but never get sick. The Yankees received the single-dose vaccine from Johnson & Johnson on April 7. This is enough time for their immune system to be fully armed against the virus. But no vaccine is perfect. “Johnson & Johnson has been 100% effective in preventing hospitalization and death, 85% effective in severe cases, and 72% effective in preventing moderate illness in various trials,” Bento says. “So we expected that if the vaccinated people become infected, they will likely be asymptomatic.”
In a bid to defeat the raging pandemic, most Covid vaccines have been tested against their ability to prevent serious illness and death. They all do it very well. “But to determine if this outbreak is consistent with the efficacy of the reported vaccine, which J&J reported against the infection, you would want to compare the rates,” says Sarah Cobey, epidemiologist and evolutionary biologist at the University of Chicago.
What we can do, almost. In vaccine trials, Johnson & Johnson researchers actually tested certain subjects for asymptomatic infection: the people in the trial who tested negative for the virus before the study then tested positive for antibodies to the virus afterwards whether or not they got sick? About two and a half months after vaccination, 2.8% of people who did not receive the vaccine were sick without symptoms. But it was the same for 0.7% of people who did to get vaccinated. It is an efficiency, a relative risk reduction, about 74.2 percent (with a fairly wide confidence interval, indicating that the statistical power here is only poor). In one pre-print Posted earlier this week (so not yet peer reviewed), independent researchers looking at actual results from the J&J vaccine two weeks after the shot found that only three of the 1,779 people vaccinated had tested positive for the virus that causes Covid-19, compared to 128 people out of 17,744 unvaccinated people. This is a very, very good rate, but not 100%.
Problem is, the Yankees haven’t said how many people overall have been vaccinated – a team spokesperson hasn’t answered my questions – so it’s impossible to say if eight groundbreaking cases are. exceptionally bad or fair for the course (if you ‘I forgive a metaphor for an entirely different sport).