More than 1000 of the aircraft carrier’s crew of nearly 4900 tested positive for COVID-19 in the outbreak.
The study by the US Centres for Disease Control and Prevention and the US Navy into a sample of 382 US Navy personnel on board, found 60 per cent of them tested positive for antibodies, and among them 59 per cent had also developed neutralising antibodies by the time blood samples were taken.
Crucially the study found that “those who reported taking preventive measures had a lower infection rate than did those who did not report taking these measures”, with the greatest protection among those who wore masks.
Only 55.8 per cent of those who wore a mask became infected compared with 80.8 per cent of those who did not. Of those who practised physical distancing 54.7 per cent had been infected compared to 70 per cent of those who did not.
Wearing a protective facial covering was also found to be more effective than increased handwashing, with around 62 per cent of those who reported regularly washing their hands becoming infected compared to around 65 per cent of those who didn’t regularly wash their hands.
The authors of the study wrote: “This report improves the understanding of COVID-19 in the US military and among young adults in congregate settings and reinforces the importance of preventive measures to lower risk for infection in similar environments.”
The report has been welcomed by UK experts who argue the wearing of masks should become far more common.
Trish Greenhalgh, professor of primary care health sciences at Oxford University, who recently completed a review on face masks, said: “This study adds to the growing weight of evidence in support of widespread wearing of face coverings in enclosed spaces where it is difficult or impossible to maintain 2 metres social distance.
Professor Sian Griffiths of Staffordshire University, who led the Hong Kong government’s investigation into the 2003 SARS epidemic, said: “Wearing masks in closed environments is a good idea and I don’t know why we aren’t pushing it more. We need leaders out there wearing masks to encourage the public to do so. It’s amazing that people still aren’t wearing them in shops. We need this as part of basic measures to get the virus down.”
A German study last week found the mandatory use of masks slows growth in COVID-19 cases by 40 per cent.
The Telegraph, London