Three Seattle fishermen who were spared coronavirus during an outbreak that affected 85 percent of the people on their boat may provide the first direct evidence that antibodies can provide immunity from the contagion, according to a new report.
Blood samples collected before the factory trawler FV American Dynasty, owned by American Seafoods, set sail in May indicated that three of the 122 people on board had high levels of neutralizing antibodies — which block the virus from entering human cells — indicating that they were once infected and recovered, the Seattle Times reported.
None of the crew members tested positive for the virus — and while six tested positive for antibodies that bind to the novel coronavirus, only those three had neutralizing antibodies, the outlet reported.
Eighteen days into its voyage, the ship returned to shore after one crew member fell ill and required hospitalization. As the other crew members were monitored for the next 50 days, 104 people were confirmed to be infected, according to the report.
None of the members with neutralizing antibodies reported any symptoms or became infected, a detail that researcher Dr. Alex Greninger called “hopeful news,” in a not yet peer-reviewed report posted on MedRxiv.
“It’s a strong indication that the presence of neutralizing antibodies is associated with protection from the virus,” said Greninger, assistant director of the University of Washington Medicine Clinical Virology Laboratory, according to the Times.
“While this is a small study, it offers a remarkable, real-life, human experiment,” Danny Altmann, professor of immunology at Imperial College London, wrote in a commentary, the paper reported. “Who knew immunology research on fishing boats could be so informative?”
Statistical analysis indicates it’s probably not a coincidence that all three of those members remained virus-free, according to the Times. However, the study doesn’t explain why 15 other crew members apparently never contracted the illness — and Greninger suggested their specific jobs shielded them from exposure.
The other crew members found to have antibodies did contract the virus, indicating that their initial results may have been false positives, according to Greninger.