As the rollout of the COVID-19 vaccine moves forward, people may be wondering what they should and shouldn't do after getting vaccinated, and when enough of society might be vaccinated to resume certain activities.

While advice and predictions vary, doctors and public health officials in southeastern Connecticut agree on a few things: People should continue to wear masks and practice social distancing measures even if they've been vaccinated, it's too soon to say when life might look more normal, and the lifting of future restrictions will depend on vaccine supply, vaccine uptake and the answers to questions scientists are still researching.

"For the immediate future, nothing will change, as far as the recommendation to mask routinely," said Dr. Patrick Cahill, infectious disease specialist at Backus Hospital in Norwich. He added that "hand hygiene recommendations should continue in perpetuity, forever, for everybody."

What if you want to have a small indoor gathering with people from different households, and everyone has been vaccinated?

Cahill said if it's been at least a week after everybody has received their second shot and you can trust that your friends and family members are being truthful about their vaccination status, "that's a reasonable scenario in which you can unmask."

Steve Mansfield, director of Ledge Light Health District, says there isn't enough data yet to say whether there should be changes to recommendations on social gatherings and social distancing.

Similarly, Dr. Oliver Mayorga, chief medical officer for Lawrence + Memorial Hospital and Westerly Hospital, said he couldn't give advice on such a gathering yet, because these kinds of questions are still being studied. But he expects there to be more scientific research in the next few months to guide people on what they can safely do after being vaccinated.

While clinical trials showed the Pfizer and Moderna vaccines are 95% effective at preventing illness from COVID-19, scientists don't yet know if people who got the vaccine and are asymptomatic can still transmit the coronavirus that causes the disease.

As for when things might change, a major factor is how many people decide to get vaccinated.

"I think the next six months are going to be critical to seeing how Americans respond to the distribution or the offering of vaccines," Mayorga said. "It's unclear how many people don't want to get it, and it's unclear how many people don't want to get it right now."

Vaccine availability and herd immunity

Even if many people do opt to get the vaccine as soon as they're eligible, there's still the issue of availability.

In November, Operation Warp Speed chief scientist Moncef Slaoui said the Trump Administration planned to have enough doses available to immunize about 20 million people in December and then about 25 million to 30 million per month. But according to the CDC, not even 7 million people had received the first dose as of Friday morning.

It's unclear yet what percentage of the population will need to be vaccinated to reach herd immunity, the level at which enough people are immune from infection to provide protection to those who are susceptible.

In the spring, experts estimated the herd immunity rate for COVID-19 at 60% to 70%. But last month, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, started citing figures as high as 75% and 85%.

In a Q&A published Dec. 31, the World Health Organization said, "The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known. This is an important area of research and will likely vary according to the community, the vaccine, the populations prioritized for vaccination, and other factors."

Similarly, Mayorga called herd immunity a "moving target" that is influenced by many different things, pointing to the new, more contagious variant of the virus as an example.

How will we know when herd immunity has been achieved?

Mayorga's guess is that it's when we see a significant drop in new cases in the community. Mansfield said he is relying on the CDC to analyze the data and calculate the percentage, saying it's not something that would be done on the local level or even the state level.

There's also the possibility that states could end up with very different vaccination rates. What happens if Connecticut sees higher vaccination rates and cases going down before the rest of the country?

Cahill said residents still shouldn't resume more normal activities yet, commenting on the ease of travel and saying we "shouldn't consider ourselves unique or an island."

Of course, states may make very different decisions on what to reopen or what to allow when, as they have done with closures throughout the pandemic.

"The mitigation measures that people have put in place have varied pretty dramatically, so I think whenever that happens, there's a lack of consistency and that can affect the public's trust about what's safe and what's not safe," Mansfield said.

But he wouldn't be surprised if different approaches are taken in different states based on herd immunity levels and transmission rates, and Mayorga thinks it's likely that a state will have restrictions lifted if it has a better vaccination rate.

Some foresee a future where people might have to show proof of vaccination to go to different places or do different activities.

"If I were to imagine what it might look like as we progress towards more vaccination, I can think that perhaps there's a vaccination passport, proof of vaccination, that allows you to attend certain events, fly to certain countries," Mayorga said. He thinks time will tell, but said maybe someone could go to a Broadway show but only if they have proof of vaccination.

Mansfield said he hasn't heard any discussion about this concept but it wouldn't surprise him if some entities decided to only provide services to people who have been vaccinated.

Dr. Ramindra Walia, chief medical officer for UCFS Healthcare, considers the vaccine another weapon that we have but not the ultimate weapon. He hopes it will become the ultimate weapon but said we don't have the information to know that yet.

Walia said with the vaccine, "we should start being hopeful, we should start being optimistic, but we shouldn't start being careless."

Mansfield said there are many variables determining what the future will look like, such as vaccine supply, how many people are willing to be vaccinated, and what herd immunity is. But he thinks if we can vaccinate a lot of the population in relatively short order, "I'm very hopeful that we'll be approaching some sense of normalcy in the middle of the year."

e.moser@theday.com