- It is difficult to avoid exposure to coronavirus in the cramped confines of a naval ship
- Sailors who take protective measures do, however, reduce their chances of contracting SARS-CoV-2
- Most young sailors tested aboard a US Navy aircraft carrier developed neutralising antibodies against the virus
When Covid-19 strikes the young, the lion's share of patients still show symptoms, a new report on a coronavirus outbreak aboard a US Navy aircraft carrier suggests.
In late March, the USS Theodore Roosevelt arrived in Guam after numerous sailors on the ship developed Covid-19. In April, the US Navy and the US Centers for Disease Control and Prevention investigated the outbreak by checking the lab findings for 382 service members on the carrier.
In the outbreak, there was widespread transmission of SARS-CoV-2 (the virus that causes Covid-19) among young, healthy adults living in close quarters who mostly showed mild symptoms, the researchers reported in June in the Morbidity and Mortality Weekly Report, a CDC publication.
Physical distancing measures mattered: Sailors who took infection prevention measures were less likely to be infected. Wearing a face mask lowered the risk from 81% to 56%; avoiding common areas lowered risk from 67.5% to 54%; and observing physical distancing lowered risk from 70% to 55%, the researchers found.
"The findings reinforce the importance of non-pharmaceutical interventions, such as wearing a face covering, avoiding common areas, and observing physical distancing to lower risk for infection in similar congregate living settings," the team led by CDC researcher Daniel Payne wrote.
Substantial challenges on board
Among 238 service members with previous or current SARS-CoV-2 infection who completed a survey, 194 (81.5%) reported one or more symptoms, 44 were asymptomatic, and two were hospitalised for Covid-19.
Current thinking on Covid-19 among young, healthy adults has been that many show hardly any symptoms.
Males were more likely to be infected than females, but there were no significant differences when it came to age, race, ethnicity or history of a pre-existing medical condition, the researchers noted.
Roughly one-third of patients had fever, body pain and chills, and these people had higher odds of SARS-CoV-2 infection than those who reported cough and shortness of breath. Participants reporting a loss of sense of smell or taste were 10 times more likely to be infected as those who did not, according to the report.
"The shipboard environment presents substantial challenges for reducing viral transmission because of congregate living quarters and close working environments," the researchers wrote. "The significant association of infection and male sex could reflect an association with berthing, which is separated by sex aboard the ship."
There was a bit of good news in the findings: Neutralising antibodies, which could potentially disable the virus, developed among the majority (just over 59%) of those with antibody responses, "a promising indicator of at least short-term immunity", the researchers concluded.