The investigation into the COVID-19 outbreak aboard the USS Roosevelt is officially complete and the findings suggest more infections than originally believed.
Volunteers were asked to complete a short survey and provide two specimens — a blood sample and nasal swab.
The study found over 60 percent (62%) of the nearly 400 sailors who participated had antibodies for the virus, meaning they were infected with COVID-19 at some point, and that most were mildly ill.
Other notable findings from the study:
- 44 (18.5 percent) of service members who were identified as having a current or previous SARS-CoV-2 infection did not report any symptoms.
- Among those who provided nasal swabs, just over one third tested positive for current infection.
- Loss of taste or smell was the symptom most associated with current or previous infection; participants reporting these symptoms were 10 times more likely to have infection than were those who did not.
- Among 12 participants with antibodies that were detected longer than 40 days after symptom onset, eight remained neutralization positive including two participants who were tested 3 months after symptom onset.
- Among all participants, current or previous infection was more common among males than females, but did not differ significantly by age, race, ethnicity, or history of a preexisting medical condition.
- Current or previous infection was higher among participants who reported contact with someone known to have COVID-19 (64.2 percent) compared with those who did not (41.7 percent) and higher among service members who reported sharing a room with another service member that tested positive (65.6 percent) compared with those who did not.
- Service members who reported taking preventive measures compared to those who did not had a lower infection rate (wearing a face covering (55.8 percent versus 80.8 percent), avoiding common areas (53.8 percent versus 67.5 percent), and observing social distancing (54.7 percent versus 70.0 percent).
This is the first CDC published report on this specific demographic of young adults.
This study is in line with previous outbreaks on cruise ships which reported undetected transmission of COVID-19 due to mild and asymptomatic infection.
Like many other respiratory viruses, the study says COVID-19 appears to spread more easily between people in close quarters including those aboard ships and boats.
Overall, the study shows young, healthy adults with COVID-19 might have mild, atypical, or no symptoms, therefore symptom-based surveillance might not detect all infections.
Researchers involved say the use of face coverings and other preventive measures could mitigate transmission in similar settings, and that the presence of neutralizing antibodies among the majority of TR participants in this study is promising, for at least short-term immunity.
At its peak, the TR reported over 1,100 positive cases.
One sailor died and a handful were hospitalized because of the disease.
Read the full report here:CDC MMWR_SARS-CoV-2 Infections and Serologic Responses from a Sample of U.S. Navy Service Members — USS Theodore Roosevelt, April 2020