What you need to know about the coronavirus right now

Sydney's unvaccinated warned of isolation when lockdown ends
Sydney residents who are not vaccinated against Covid-19 risk being barred from various social activities even when they are freed from stay-at-home orders in December, New South Wales state Premier Gladys Berejiklian warned on Tuesday.

The two-tier system, designed to encourage more people to get vaccinated, has been criticised for both penalising vulnerable groups who have not had access to inoculations and for falling short of providing a real incentive for the vaccine hesitant.

New York hospitals fire, suspend staff who refuse vaccine
New York hospitals on Monday began firing or suspending healthcare workers for defying a state order to get the Covid-19 vaccine, and resulting staff shortages prompted some hospitals to postpone elective surgeries or curtail services.

New York City Mayor Bill de Blasio told a news conference the city's hospitals were not yet seeing a major impact from the mandate, adding he worried about other areas of the state where vaccination rates are lower.

Japan to end Covid-19 state of emergency this month
Japan will lift a coronavirus state of emergency in all regions on Thursday as the number of new cases falls and the strain on the medical system eases, Economy Minister Yasutoshi Nishimura said. The plan, approved by a government advisory panel, takes Japan as a whole out of an emergency state for the first time in nearly six months.

But Nishimura said some limitations on eateries and large-scale events would remain in place for about a month to prevent a resurgence in cases. Restaurants in areas under emergency curbs are now required to close by 8 p.m. and not serve alcohol.

Virus-infected cells protected from immune system by protein
A protein called CD47 that helps damaged cells avoid destruction by the immune system may be contributing to severe cases of Covid-19, researchers believe. Drugs in development targeting CD47 may result in improved Covid-19 therapies, they suggested in a report published in Current Issues in Molecular Biology.

In lab experiments, the researchers found that CD47 - which in effect tells the immune system, "Do not eat me!" - is present in increased amounts on the surfaces of cells infected with the coronavirus. SARS-CoV-2 infection also increases levels of another protein, SIRPalpha, that partners with CD47 to trick the immune system into ignoring the sick cells.

India reports smallest rise in Covid-19 deaths since mid-March
India reported 179 Covid-19 deaths on Tuesday, the lowest daily toll since the middle of March, taking the total to 447,373.

Infections rose by 18,795, the smallest increase since early March, lifting the total to about 33.7 million, health ministry data showed.