This Trawler’s Haul: Evidence That Antibodies Block the Coronavirus

“People have been so worried about the titers, and the titers going down,” Dr. Alexander Greninger, a virologist at the University of Washington in Seattle, said.

The results indicate even moderate titers prevented reinfection in a situation in which exposure to the virus was high, he said: “These are attainable titers, right? Hopefully, it’ll be helpful to see, and makes make me very optimistic about the vaccines.”

The American Dynasty carried 113 men and nine women. All crew members had been tested for both virus and antibodies as part of a routine screening before setting sail. (The researchers did not have access to the results from two members.)

The trawler returned to shore after 18 days at sea when a crew member became ill enough to need hospitalization. The sailors were tested for the presence of virus and antibodies again and for up to 50 days after their return.

The three sailors confirmed to have neutralizing antibodies did not test positive for the virus during the course of the study; 103 of the remaining 117 became infected.

These numbers may be small, but they’re highly significant, Dr. Greninger said.

“A lot of people, when they see this are like, ‘Oh come on, it could be due to random chance,’” he said. In fact, the likelihood that the results are just chance is extremely low, he added.

Other experts agreed. “Just looking at the numbers, it becomes clear that it’s unlikely that all of these three people were protected by chance,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York.