US Navy/MCS 3rd Class Zachary Wheeler
A severe coronavirus outbreak hit the USS Theodore Roosevelt, a Navy aircraft carrier stationed in the Pacific, in late March and April.
Nearly one-quarter of the carrier's 4,800-person crew was infected.
A new study shows that one in every five infected sailors showed no symptoms, and just 60% of those infected developed coronavirus antibodies.
The researchers also found that sailors who wore face masks, avoided common areas, and practiced social distancing were less likely to become infected.
The sailors aboard the USS Theodore Roosevelt are young and healthy, with few underlying medical conditions.
That didn't stop the coronavirus from wreaking havoc aboard the Navy ship, infecting nearly one-quarter of the 4,800-person crew in late March and April. The severe outbreak forced the Navy ship to dock in Guam for two months, while every crew member was tested and 80% of the ship was cleaned and disinfected.
Related: How Data Can Help Track, Stop the Spread of COVID-19
Now, new research published Tuesday from the Centers for Disease Control and Prevention (CDC) reveals what conditions aboard the cramped carrier facilitated that spread.
The study found that one in every five infected sailors had no symptoms, and just 60% of a group of infected crew members developed antibodies that could neutralize the virus.
US Navy/MCS 3rd Class Zachary Wheeler
"This finding may give us an early glimpse into actual immune protection against [the coronavirus] in young adults having these intense viral exposures aboard the ship," Daniel Payne, a CDC epidemiologist and the study's lead author, told Stars and Stripes.
Antibodies are 'a promising indicator of at least short-term immunity'
The USS Theodore Roosevelt reported its first COVID-19 cases on March 24, docking a few days later in Guam so more than 80% of the crew could be evacuated ashore and isolated in hotels to prevent further spread
Only 382 of those 1,273 infected sailors volunteered to participate in the CDC study.
Between April 20 and 24, those 382 sailors filled out questionnaires about their habits aboard the ship and provided samples for antibody testing. Three-quarters of that cohort were male crew members, about 60% were non-Hispanic white, and their average age was 30 years.
Antibody tests revealed that nearly 60% of those 382 study participants had developed neutralizing antibodies, proteins that help our bodies disable the invading virus. In several infected sailors, those antibodies were still detectable more than 40 days after they started showing symptoms, which the study authors said was "a promising indicator of at least short-term immunity."
US Navy/MCS Seaman Dylan Lavin
The value of this study, Payne said, is that it's the first to examine how the virus spreads within a group of young, healthy adults — a cohort at far less risk of developing severe coronavirus cases than older individuals with preexisting health problems.
The carrier's antibodies results go against scientific evidence suggesting that nearly everyone who has had COVID-19 — regardless of age, sex or severity of illness — should develop antibodies.
One May study found that 20 coronavirus patients, including two people with severe cases that required hospitalization, all developed antibodies to fight the virus. The average age of those patients was 44.
For now, it's unclear why the remaining 40% of young, healthy participants from aboard the Navy carrier didn't have these neutralizing proteins.
About one in five infected sailors were asymptomatic
Payne and his colleagues found that 18.5% of the 382 study participants, so roughly one in five, showed no symptoms despite being infected. Among the 284 symptomatic sailors, loss of smell and taste were the most common symptoms, followed by fever and chills.
The risk of infection was double for crew members who shared a berth with someone who'd tested positive.
U.S. Navy photo by Mass Communication Specialist 3rd Class Conner D. Blake
The CDC study authors also found that sailors who reported wearing face masks were less likely to become infected, as were those who avoided common areas and practiced social distancing.
Now that the USS Theodore Roosevelt is back on active duty in the Pacific, these findings could inform additional safety and health precautions onboard.
Navy officials are now working to "tailor our public health practices to the unique characteristics of this adversary whose secret weapon, as you know, is the ability to be transmitted by an individual before they know they're infected," Rear Adm. Bruce Gillingham, the US Navy surgeon general, said in a Tuesday media briefing.
Read the original article on Business Insider