1) Face masks
The novel coronavirus spreads by droplets from coughs, sneezes and speaking. To halt the spread of the virus, face masks have become compulsory in many countries.
But there has been much debate among scientists over the effectiveness of face masks on reducing the spread of COVID-19. A report from a multidisciplinary group convened by the Royal Society has come out in favour of the public wearing face masks. These documents, which have not been peer reviewed, argue that face coverings can contribute to reducing the transmission of COVID-19 if widely used in situations where physical distancing is not possible.
One relatively small clinical study also showed that infected children who wore masks did not pass on the virus to family contacts.
But the science is complex. Face masks won’t stop the wearer from inhaling small airborne particles of coronavirus, which can cause infection. A recent study reported that wearing a mask may also give a false sense of security, meaning wearers may ignore other important infection control measures.
Research has also shown that when people wear masks, the exhaled air goes into the eyes. This generates an impulse to touch the eyes. And if your hands are contaminated, you may infect yourself. Indeed, WHO warns that masks can be counterproductive unless wearers avoid touching their face and adopt other management measures.
We also know that face masks can make us breathe more often and more deeply – potentiality spreading more contaminated air.
Many scientists therefore disagree with the Royal Society report, requesting more evidence on the efficacy of masks. Ideally, we need randomised controlled trials involving many people from an entire population to trace how masks affect infection numbers.
That said, other scientists argue that we should use face masks even though perfectly reliable evidence is lacking – to be on the safe side. Ultimately though, without a vaccine, the strongest weapons we have are basic preventive measures such as regular hand washing and social distancing.
2 ) Immunity
Immunologists are working hard to determine what immunity to COVID-19 looks like. Much of the studies have focused on “neutralising antibodies”, produced by so-called B-cells, which bind to viral proteins and directly prevent infection.
Studies have found that levels of neutralising antibodies remain high for a few weeks after infection, but then typically begin to wane. A peer-reviewed study from China showed that infected people had steep declines in levels of antibodies within two to three months of infection. This has created doubt over whether people get long-term protection against subsequent exposure to the virus. If this study turns out to be accurate – the result needs to be backed up by other studies – it could have implications for whether it is possible to produce vaccines with long-lasting immunity.