USS Theodore Roosevelt: Study finds 60% of sailors have antibodies against Covid-19, hinting at short-term immunity
The report on Covid-19 outbreak on USS Theodore Roosevelt shows how Covid-19 affects the young and healthy
Most young and healthy adults aboard USS Theodore Roosevelt aircraft carrier -- where Covid-19 broke out in late March -- showed mild or no symptoms, according to a report from the Centers for Disease Control and Prevention (CDC). What is more, the investigation also found that 60% of the sailors in the study developed antibodies against the virus, hinting that recovered patients may develop short-term immunity.
"This is the first major look at Covid-19 infections among healthy young adults that the CDC has released," said Daniel Payne, an epidemiologist who worked on the investigation, reports CNN. The report also found that sailors who wore masks or practiced social distancing were more protected than their counterparts who did not follow these safety measures. More than 1,000 members or 24% of the ship's crew contracted the infection, according to the report.
The Covid-19 outbreak on the USS Theodore Roosevelt aircraft carrier helped scientists fill a major gap in information on how the disease strikes the young as there is more data on older adults in the US. "What we saw was that most of the infections were mild, in addition to those that were asymptomatic," Payne told reporters Tuesday, June 9. "And this is perhaps different from studies of older Americans, or maybe even those who were hospitalized already, and certainly much different from those with underlying health conditions."
Because many young people show mild or no symptoms, the investigation suggests that temperature screening might not be effective at catching the disease in this population. "Symptom-based surveillance might not detect all infections," the report said. In this study, the United States Navy and the CDC carried out investigations between April 20–24. They interviewed 382 service members, who also provided samples for antibody tests. The median age of the participants stood at 30.
The CDC and the US navy asked the 382 volunteers to fill out a questionnaire about symptoms, exposure, Covid-19 protective behaviors, and health history. Nearly 7% of them reported a history of health conditions such as asthma, hypertension, diabetes, and others. About 62% tested positive for Covid-19, but 18.5% of them said they had not experienced any signs of the disease. The scientists found that protective measures could shield people from the disease. About 55.8% of those who used face-covering contracted the infection, compared to 80.8% who did not. And nearly 55% of sailors who practiced physical distancing developed the disease, compared to 70 % who mingled with others.
Blood tests showed that about 60% of them developed antibodies against the virus. Among them, 59% of them had neutralizing antibodies, which binds to the new coronavirus virus and weakens it, thereby blocking an infection. These antibodies stayed for more than 40 days in 12 participants after the symptoms took off. The scientists add more studies will need to provide information on whether immunity can last for longer periods.
The CDC report highlights a few limitations in the study, including that the gathered data was from memory. In other words, people may have incorrectly recalled information about their symptoms or other details. However, the report improves the understanding of Covid-19 among young adults, say experts. Officials are now trying 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, told reporters Tuesday.