PROVIDENCE – President Biden’s just-announced new goal of administering 1.5 million doses of coronavirus vaccines daily is “real and important,” Dr. Ashish Jha asserted on Tuesday – but the dean of Brown University’s School of Public Health said he would

COVID: What comes next - With Dr. Ashish Jha

Speaking during the weekly taping of the national “COVID: What Comes Next” podcast, Jha said “I believe if things go well on production that we will be on track to be able to produce almost 2 million doses a day, and I want to make sure that there is a very short line between production of doses and vaccinations into people's arms.”

Vaccines from Moderna and Pfizer-BioNTech are currently being manufactured and distributed in the U.S., with new products from Johnson & Johnson and Astra-Zeneca heading toward likely emergency use authorization in the weeks to come. A fifth vaccine, from Novavax, is currently in clinical trials.

Jha said the emergence of COVID-19 variants warrants a more ambitious dosing plan. Several mutations of the virus have been identified, with the so-called British variant and one seen in South Africa of particular concern, given that both are more easily transmissible and the South Africa variant may be more resistant to vaccines – a possibility that has prompted Moderna to develop a booster shot. Variants have also been identified in California and Brazil.

For people who have been vaccinated, Jha said “all the evidence I see so far says you'll still have protection against the South Africa variant, but it may not be quite as strong a set of protection. So you may still get infected but you'll have milder disease and you probably will be less likely to be infected. We just don't know right now. There's a lot we're still sorting out but I guess my point is: it's not a moment of panic.”

The South Africa variant has not been discovered in the U.S., but Jha said it is inevitable that it will reach America, regardless of travel restrictions that have been enacted. The Brazil variant has just been detected in Minnesota and the British variant is spreading widely.

“There is zero chance in my mind that we will be able to keep any of these variants completely out,” Jha said. “The point of travel restrictions in my mind is not to keep these things completely out, that's not realistic. It's just to slow the spread. So instead of 1,000 people coming in with a variant and letting it take off, maybe only 20 will or 10 will and that means it'll spread much more slowly and you'll have more time to get it and catch up to it and identify it.”

Asked if more variants will emerge, Jha said “undoubtedly,” but the number and type “depends a little bit on what we do. Remember that these variants arise when we give the virus a chance to mutate -- and viruses mutate the more they replicate. So as long as these outbreaks remain very, very large, as long as we have large numbers of people infected, there will be more opportunities for variants.”

He added: “We can reduce the number of variants that arise by keeping the level of infections really low. There are many reasons to vaccinate lots of people quickly and one of them is ‘I want to bring this pandemic under control.’ By bringing it under control, we will actually reduce the risk of new variants arising.”

During the podcast, available from The Providence Journal and the USA TODAY NETWORK, Jha also answered two audience questions.

-- One person asked what to do if you receive a first dose of the Moderna or Pfizer vaccines but the recommended second dose is not available from the same manufacturer – should you take a second dose from the other manufacturer, a Pfizer shot after a first-dose Moderna, or vice versa?

“As a general rule, people should absolutely get the same one,” Jha said. “In extremely unusual circumstances, it may be fine to get another second one, but I do not think that should be the default. We should generally try our best to avoid mixing and matching.”

-- Another person asked: “Is there any data regarding the side effects of receiving the COVID vaccine along with the new shingles vaccine within the same timeframe or within a few months from each other?”

Jha said “the short answer here is we don't know we don't have enough clinical data.”

For the dean’s full answers and more about variants and vaccines, please listen to the full podcast.

This weekly podcast is hosted by G. Wayne Miller, health reporter for The Providence Journal.