Coronavirus update: Latest Covid-19 and vaccine news

For indoor events, the threshold drops to 5,000 attendees where those without proof of vaccination or a negative Covid-19 test will be required to wear a mask, according to Ghaly.So-called vaccine passports are not being considered at this time, Ghaly said.Over 35 million vaccine doses have been administered to date in California and the state continues to push availability, bringing efforts deeper into communities and incentivizing shots. CNN correspondent Leyla Santiago reports from Miami and answers viewers' questions.Watch: From CNN's Jacqueline HowardCovid-19 case numbers in elementary schools appear to be 37% lower when teachers and staff are required to wear masks, and 39% when air ventilation is improved, according to new research published by the US Centers for Disease Control and Prevention.The findings are based on data from before coronavirus vaccines became available, but until children younger than 12 are eligible for the vaccine, "universal and correct mask use is a critical prevention strategy CDC recommends that schools prioritize regardless of vaccination status for in-person learning," according to the study published on Friday.Despite vaccinations beginning for children ages 12 to 15 and CDC’s changing mask guidance for fully vaccinated people, the agency has said schools should continue masking and using other coronavirus prevention strategies for at least the rest of the 2020-2021 school year. They also assessed responses from an online survey that was emailed to the school superintendents, asking about the Covid-19 prevention strategies implemented within the schools at the time — including mask-wearing and air ventilation.The researchers found that, while the incidence of Covid-19 was lower in schools that required masks, it varied depending on whether the staff or the students were required to wear masks. "These findings suggest that there are opportunities for many schools to reduce SARS-CoV-2 transmission through improved ventilation."More research is needed to determine whether similar findings may emerge in other parts of the United States and in data that are not self-reported or based on online surveys.From CNN's Betsy KleinThe Biden administration wants Americans to keep forging ahead with vaccinations, a messaging balance that the nation “can’t take our foot off the accelerator” despite the pandemic’s improving outlook across the country.But, Murthy warned, “If we stop where we are right now, if people do not get fully vaccinated and millions more out there who still need to, then we will still be at risk potentially for more infections in the future.”Murthy’s comments come as the US has seen sustained decreases in Covid-19 cases, hospitalizations, and deaths. White House senior Covid-19 adviser Andy Slavitt added that the administration has more work to do on educating Americans about vaccinations but said “many, many more people will get vaccinated.”From CNN's Naomi Thomas More than 3 million excess deaths in 2020 could be related to Covid-19 – over a million more deaths than what was reported globally, according to preliminary data from the World Health Organization.The report says that preliminary assessments of excess mortality estimate that during 2020, there were 1.34 to 1.46 million excess deaths in the region of the Americas and 1.11 to 1.21 million in the European region.