What you need to know about the coronavirus right now
U.S. FDA clears Pfizer booster for older and at-risk Americans
The U.S. Food and Drug Administration on Wednesday authorised a booster dose of the Pfizer Inc and BioNTech Covid-19 vaccine for those 65 and older, all people at high risk of severe disease, and others who are regularly exposed to the virus.
The decision paves the way for a quick rollout of the booster shots as soon as this week for millions of people who had their second dose of the vaccine at least six months ago.
Melbourne braces for anti-lockdown protests
Police in the Australian city of Melbourne prepared for a fourth day of anti-lockdown protests on Thursday while a vaccination hub closed after protesters abused staff, the operator said, while Covid-19 cases across the state of Victoria hit a daily record. Hundreds of protesters have taken to the streets in the city of 5 million since officials this week ordered a two-week closure of building sites and made vaccines mandatory for construction workers to limit the spread of the virus.
A vaccination centre at the Melbourne Town Hall would be shut until Monday, operator cohealth said, after several of its staff were physically and verbally abused on their way to work.
New variants may spread more efficiently into air
The virus that causes Covid-19 may be getting better at travelling into the air, a new study suggests. Researchers found that patients infected with the Alpha variant of the virus - the dominant strain circulating when the study was conducted - put 43 to 100 times more virus into the air than people infected with the original version of the coronavirus. Some of this was due to the fact that patients infected with Alpha had increased amounts of virus in nasal swabs and saliva.
But the amount of virus being exhaled was 18 times more than could be explained by the higher viral loads, according to a report published in Clinical Infectious Diseases. Researchers also found that loose-fitting face coverings worn by patients with mild Covid-19 can reduce the amount of virus-laden particles in the surrounding air by about 50%.
England's top medic says transmission highest in children
England's Chief Medical Officer Chris Whitty said on Wednesday that Covid-19 transmission was highest in 12- to 15-year-olds, and that almost all unvaccinated children would get infected at some point.
Although around half of children have probably already had Covid-19, he said, protection may wane and a vaccination programme would be less disruptive to schools than if the children caught Covid-19.
Alaska adopts crisis standards for hospitals
Alaska, which led most U.S. states in coronavirus vaccinations months ago, took the drastic step on Wednesday of imposing crisis-care standards for its entire hospital system, declaring that a crushing surge in Covid-19 patients has forced rationing of strained medical resources. About one-fifth of Alaska hospital patients are infected with Covid-19, according to state data.
Alaska's health and social services commissioner, Adam Crum, announced that he signed an emergency addendum extending to the whole state standards of crisis care announced last week at the state's largest hospital, Providence Alaska Medical Center, in Anchorage. The document limits liability faced by providers for crisis-level medical care in all Alaska hospitals.