COVID19 🦠 Newsbites
Covid vaccines may not reach a quarter of the world's people until 2022, study finds
Nearly a quarter of the world may be unable to get vaccinated until 2022 because high-income countries like the US have hoarded the lion’s share of vaccine doses, researchers reported Tuesday.

Rich countries have reserved just over half (51%) of the most promising vaccines, while low- and middle-income countries will have to share the remainder -- despite being home to more than 85% of the world's population, according to a new report by the Johns Hopkins Bloomberg School of Public Health in the US.

At the time the report was written, the US accounted for one-fifth of all global Covid-19 cases but had reserved 800 million doses of vaccine. Japan, Australia and Canada accounted for fewer than 1% of cases but had options on more than 1 billion doses.

It is yet another reminder that initial global demand will vastly outstrip supply -- a reality that has given rise to vaccine nationalism and prompted concerns about inequitable allocation of doses.

Why a Covid-19 vaccine doesn't mean that you can stop wearing a mask
While these developments mark a historic moment and hold much promise, that doesn't mean Americans can stop wearing masks anytime soon. CNN Medical Analyst Dr. Leana Wen, an emergency physician and visiting professor at George Washington University Milken Institute School of Public Health, explains why.

They haven't looked at whether the vaccine prevents someone from carrying Covid-19 and spreading it to others. It's possible that someone could get the vaccine but could still be an asymptomatic carrier. They may not show symptoms, but they have the virus in their nasal passageway so that if they're speaking, breathing, sneezing and so on, they can still transmit it to others.

This is the main reason why we can't stop wearing masks right after we get the vaccine. The vaccine will protect you from getting ill and then ending up hospitalized. But it's possible that you could still carry the virus and be contagious to others. So those who get the vaccine should still be wearing masks and practicing physical distancing.

It's estimated that about 70% of Americans must be vaccinated before we get to herd immunity through vaccination. That's the point where enough people have the immune protection that the virus won't spread any more.

This means about 230 million Americans must receive the vaccine. It will take time to produce this many vaccines — and remember the Pfizer and Moderna vaccines are two-dose vaccines, so you need double the number of doses as people. Then the vaccine must be distributed and actually given to people. If all goes well, the best estimates are that it will be late spring or early summer for most Americans to receive the vaccine. At that point, we could probably see one another without masks — but not before.

It's very important to prevent the virus from reaching your body in the first place. Wearing a mask does that. So does physical distancing. These are really important measures to prevent from getting coronavirus and transmitting it to others.

You will certainly see mask wearing among health care workers, who will be among the first groups to get the vaccine. The vaccine is one important layer of protection for us, but we will use these other measures to protect ourselves and those around us.