Here's what you need to know about the coronavirus right now:
Delay Pfizer vaccine's second dose, researchers say
Researchers on Wednesday urged governments to delay administering the second dose of Pfizer Inc's Covid-19 vaccine, which they said had an efficacy of 92.6% after the first dose.
They cautioned that there may be uncertainty about the duration of protection with a single dose, but said that the administration of the second dose a month after the first provided "little added benefit in the short term".
Pfizer says South African variant could significantly reduce vaccine protection
A laboratory study suggests that the South African variant of the coronavirus may reduce antibody protection from the Pfizer Inc/BioNTech vaccine by two-thirds, and it is not clear if the shot will be effective against the mutation, the companies said on Wednesday.
The study found the vaccine was still able to neutralize the virus and there is not yet evidence from trials in people that the variant reduces vaccine protection, the companies said. Still, they are making investments and talking to regulators about developing an updated version of their mRNA vaccine or a booster shot, if needed.
S.Korea's vaccine goals 'practically impossible', medical body's chief says
South Korea will almost certainly miss its goal of vaccinating 80% of its population to reach coronavirus "herd immunity" by November, the head of a doctors' association whose advice helped the country contain the pandemic's first wave said on Wednesday. The vaccination programme is due to start next week, after a procurement process that has drawn complaints at home for being slower than many abroad.
The government now aims to immunize close to 44 million people - four in five of the population - by October to reach herd immunity four weeks later when vaccine antibodies will have been formed. The government's plans calls for each physician to diagnose and vaccinate 150 patients a day.
Covid-19 breath test shows promise in study
A commercially available electronic "nose" manufactured by Dutch company Breathomix can tell when a person does not have Covid-19 and would be a useful screening tool, researchers have found.
Studying more than 4,500 individuals who came to coronavirus test facilities in the Netherlands between August and December 2020, the device was able to reliably rule out infection - with or without symptoms - in 70% to 75% of all individuals tested, with results available within seconds.