A healthcare worker administers a Pfizer / BioNTech Covid-19 vaccine in Pompano Beach, Fla. On Jan. 6. Joe Raedle / Getty Images

Even as the US broke a record for the number of Covid-19 deaths reported in a single day, Dr. Paul Offit told CNN’s New Day several reasons to hope that the coronavirus situation could “improve dramatically” soon.

Offit, director of the Vaccine Education Center at Philadelphia Children’s Hospital and a member of the US Food and Drug Administration’s Advisory Committee on Vaccines and Related Biological Products, admitted the “terrible” numbers are likely to last for a few more months, but said they are there Reasons for optimism:

Mass vaccinations

There are two “remarkably effective” vaccines and “we’re finally starting to give bulk vaccines,” Offit said, citing examples like the Pennsylvania Convention Center and Dodger Stadium. Meanwhile, two other vaccines – those from Johnson & Johnson and AstraZeneca – are “just around the corner,” he added.

Warm weather

“The weather gets warmer when the weather gets warmer, which makes it a lot harder for this virus,” Offit explained that the virus, which spreads by small droplets, spreads less easily when it’s hot and humid.

New political administration

Offit said the incoming Biden administration “is not into the cult of denialism” that surrounded the Trump administration’s coronavirus response and would “address this issue head on.”

A population that is building immunity

The number of people reported to be infected with coronavirus – 23 million – is an underestimate, according to Offit. Many people had asymptomatic or mildly symptomatic infections and were never tested. The numbers that have been infected are likely closer to 65 or 70 million, he said.

“That’s 20% of the population who if exposed to this virus again won’t get it,” he said, although it is not clear how long immunity lasts after infection.

If another 55 to 60% of the population can be vaccinated – something that Offit said could be done in a million to a million and a half doses a day – then I really think we can stop the spread of this by June Virus.”