COVID-19: Top science stories of the week, from lingering antibodies to life-saving steroids

Icelandic study shows that antibodies persist for four months

A study published this week in the New England Journal of Medicine shows that protective antibodies against the new coronavirus can remain at a steady level in the body for up to four months after infection.

Researchers in Iceland tested the blood of 30,576 people for antibodies. In more than 1,200 who had tested positive for COVID-19 and recovered from it, 90% had antibodies against the virus. Antibody levels were higher in older people and in those more severely affected by SARS-CoV-2 infection.

Earlier evidence suggested that immunity to COVID-19 could disappear within three months. As researchers move ahead with clinical trials for vaccine candidates, a better understanding of antibodies and how consistently and sustainably they can provide protection will be needed.

Dexamethasone and hydrocortisone could help with severe COVID-19

A meta-analysis of seven different clinical trials, published in the Journal of the American Medical Association this week, has shown that using inexpensive, readily available steroid drugs – such as dexamethasone or hydrocortisone – to treat people hospitalized with COVID-19 reduced the risk of death by one-third. The results have led to new recommendations from the World Health Organization (WHO) that doctors should give them to patients with “severe and critical” COVID-19 for 7-10 days.

The new analysis builds on the results of one large-scale earlier this year when a team from Oxford University found that dexamethasone could prevent one in eight deaths among the severely ill. The results of that trial, along with six others that form the latest meta-analysis, have concluded that another steroid, hydrocortisone, also can save lives.

Steroids are the first, and so far only, therapy shown to improve the odds of survival for critically ill patients with COVID-19. In the absence of a vaccine, the results are promising but the WHO cautioned against use of the steroids in patients with non-severe illness, saying that “indiscriminate use of any therapy for COVID-19 would potentially rapidly deplete global resources and deprive patients who may benefit from it most as potentially life-saving therapy.”

Visualization shows plastic visors may not protect against COVID-19 spread

A new study published this week in the journal Physics of Fluids shows that small droplets can easily move around the sides of plastic visors and they may not be the best barrier to prevent the spread of COVID-19 when compared to regular cloth masks.

Researchers used visualization technology to map droplets from a simulated cough and found that while face shields initially block some droplets, small droplets can easily move around the sides of the visor and eventually spread over a large area.

The simulations in the new study "indicate that face shields and masks with exhale valves may not be as effective as regular face masks in restricting the spread of aerosolized droplets," the authors wrote.

Face coverings have become increasingly accepted as one of the most effective ways to combat the spread of COVID-19 but there is an increasing trend of people substituting cloth or surgical masks with plastic face shields or masks equipped with exhalation valves.

While further studies will be needed to corroborate the results, the observations from this study suggest that the use of visors could indeed have an adverse effect on the spread of COVID-19 and efforts should be made to encourage the use of regular cloth or surgical masks.