What you need to know about the coronavirus right now

HERE'S what you need to know about the coronavirus right now:

Tokyo area state of emergency to be lifted on Sunday

The Japanese government's advisory panel on coronavirus measures approved on Thursday a plan to let the state of emergency expire in the Tokyo area as scheduled on March 21, while the capital's governor warned citizens not to let down their guard.

Prime Minister Yoshihide Suga had flagged the move on Wednesday, saying the availability of hospital beds had improved in Tokyo and its three neighbouring prefectures, where restrictions have been in place since early January.

While under pressure to bring COVID-19 under control ahead of the Tokyo Olympics this summer, the government is eager to jumpstart economic activity in the Greater Tokyo area, whose 36 million residents account for 30% of Japan's population.

Virus variants found to be deadlier, more contagious; some may thwart vaccines

The coronavirus variant first identified in the UK, known as B.1.1.7, is deadlier than other variants circulating there, a new study appears to confirm. For every three people who died within four weeks after being infected with another variant in England between mid-November and mid-January, roughly five died who had been infected with B.1.1.7, according to a paper posted on medRxiv ahead of peer review.

Between November and January in Manaus, Brazil, the frequency of COVID-19 cases involving the P.1 coronavirus variant increased from non-existent to 73%, and the number of infections there quadrupled compared to what the city experienced in the first wave of the pandemic, according to another report posted on medRxiv ahead of peer review. The greater infectiousness of the P.1 variant likely contributed to that, the report suggests.

Most worryingly, antibodies induced by the Moderna Inc and Pfizer Inc/BioNTech vaccines are dramatically less effective at neutralizing some of the most worrying coronavirus variants, a third new study suggests. All five highly resistant variants had mutations in the spike on the virus surface - known as K417N/T, E484K, and N501Y - that characterise a variant rampant in South Africa and two variants spreading rapidly in Brazil.

How worried should we be about reports of blood clots and AstraZeneca's vaccine?

The European Medicines Agency (EMA) is investigating reports of 30 cases of unusual blood disorders out of 5 million people who got the AstraZeneca vaccine in the European Union. The EMA's focus and primary concern is on cases of blood clots in the head, a rare condition that's difficult to treat called cerebral venous thrombosis (CVT).

EMA investigators are checking if the frequency of incidences is higher in the vaccinated population than normal background rates.

A spokeswomen for Germany's vaccine authority, which is part of the investigation, said EMA would not rule on causality. Instead, EMA will assess the likelihood of an increased risk of the condition and weigh that against the benefits of fighting COVID-19 and providing relief for health systems.

COVID-19 reinfection rare, but more common in older people, study finds

The majority of people who have had COVID-19 are protected from getting it again for at least six months, a study published on Wednesday showed, but older people are more prone to reinfection than younger people.

The study, appearing in the Lancet medical journal, found that just 0.65% of patients tested positive a second time for COVID-19 after previously being infected during Denmark's first and second waves. That was much lower than the 3.27% who were positive for the virus using highly accurate PCR tests after initially being negative. However, the study found that people over the age of 65 had only 47% protection against repeat infection, compared to 80% protection for younger people.

"These data are all confirmation, if it were needed, that for SARS-CoV-2 the hope of protective immunity through natural infections might not be within our reach and a global vaccination programme with high efficacy vaccines is the enduring solution," Imperial College London professors Rosemary Boyton and Danny Altmann said in a linked comment piece also published in the Lancet.