‘The end is in sight’: Experts express optimism about COVID-19 pandemic coming to a close

A sign of hope in Boston on Washington Street back at the beginning of the coronavirus pandemic in March.Jonathan Wiggs/Globe Staff

While the coronavirus continued to rip through the country and daily counts of new infections rose to record heights, the seemingly impossible occurred: good news.

Promising trials from Pfizer and Moderna suggest that highly effective COVID-19 vaccines could be available in a matter of weeks, bringing the end of the pandemic in view for the first time since March.

But the end of the pandemic does not necessarily mean the eradication of COVID-19, epidemiologists said. The closing act of this public health calamity is likely to be a gradual return to a new normal, with infections, restrictions, and public health fears falling away one by one rather than all at once. Getting there will not be as simple as getting a shot, but with effective vaccines, robust distribution plans, widespread testing, and continued social distancing through the winter — all possible but hardly assured — our exit from the pandemic could come much sooner than many dared hope.

“The virus is not likely to go away, maybe ever, but certainly not for a long time,” said Dr. Ashish Jha, dean of the Brown University School of Public Health. “But that said, we’re not going to be living like this forever, and in fact, I expect by springtime that things will start really getting much, much better. And then it’ll continue to get better. And at some point, we will no longer feel like we’re living in the middle of a pandemic.”

The wave of optimism surrounding the pandemic’s end seems in some ways oddly timed, as it coincides with the worst wave of infections the United States has seen thus far. In the past week, the country recorded over 1 million new cases.

Dr. Rafik Abdou checked on a COVID-19 patient at Providence Holy Cross Medical Center in the Mission Hills section of Los Angeles on Nov. 19. California is imposing an overnight curfew on most residents as the most populous state tries to head off a surge in coronavirus cases that it fears could tax its health care system.Jae C. Hong/Associated Press

Massachusetts’ daily count of new cases last week averaged over 2,000, the highest level of new infections the state has seen since spring.

But in the past week, two vaccine developers have announced breakthroughs with the potential to help prevent future surges. Drugmakers Moderna and Pfizer have said their vaccines showed more than 94 percent efficacy in trials — meaning they reduced the occurrence of disease in vaccinated people by 94 percent compared to people who were given a placebo shot.

This far exceeds scientists’ hopes for a coronavirus vaccine. For comparison, flu shots have usually been less than 50 percent effective in recent years. Good news from Moderna and Pfizer also gives reason to hope that other drugmakers, including Johnson & Johnson and AstraZeneca, will also produce highly effective vaccines.

The news drew hopeful remarks from Dr. Anthony Fauci, the nation’s top infectious disease expert. If all goes as planned with these two vaccines, as many as 20 million Americans could be inoculated against the disease by the end of the year, he said at a Tuesday virtual event. While an impressive starting point, that number represents about 6 percent of the US population and barely exceeds the country’s 18 million health care workers.

There are limitations to what we know about these vaccines, experts said. Generally speaking, vaccines can protect against infection itself or against symptomatic illness. It remains unclear which type of protection the Moderna and Pfizer coronavirus vaccines provide. If they only prevent illness, not infection, vaccinated people could still spread the disease to others. How long immunity lasts after vaccination is also an open question. And even if these details work out favorably, mass-producing the vaccines and distributing them to the nation’s hospitals, primary care practices, and pharmacies will be a herculean task.

A health worker injected a person Sept. 9 during a clinical trial for a Pfizer COVID-19 vaccine at Research Centers of America in Hollywood, Fla.Eva Marie Uzcategui/Bloomberg

“The end will be more slow and ambiguous. It won’t be like the end of a war where there’s an announcement and then it’s over,” said Helen Jenkins, a Boston University epidemiologist. “As people get vaccinated, we’ll start to slowly see reduction in transmission.”

The timeline for that reduction depends almost entirely on vaccine distribution, Jenkins said. There is also reason to worry that a considerable number of Americans will be hesitant to get vaccinated, with one survey showing significant variation in coronavirus vaccine trust from state to state.

Besides hurdles on the way to mass-vaccination, some characteristics of this global COVID-19 outbreak make an abrupt, clear ending unlikely, experts said.

Dr. Nahid Bhadelia was a physician on the ground during the West African Ebola epidemic. The World Health Organization declared that a country’s Ebola outbreak had ended only when the country saw no new cases for 42 days — two times the length of Ebola’s incubation period.

“What you want to see is that there’s no community transmission of the disease,” said Bhadelia, an associate professor of medicine at Boston University School of Medicine and an infectious disease physician at Boston Medical Center. “It’s not going to be that easy with COVID-19, because it’s so widespread, there’s asymptomatic cases, and there’s even a question of whether COVID will go away.”

Instead of being eradicated, the coronavirus that causes COVID-19 could continue to cycle through the world’s population at intervals, like influenza viruses and other coronaviruses, Bhedalia explained. In that case, the pandemic will end when enough people are vaccinated that population level herd immunity thwarts COVID-19′s ability to spread easily.

But significant and positive changes to daily life could come well before that endpoint, said Jha, the Brown University dean.

“Once you have 20 to 30 percent of people vaccinated . . . it’ll really start slowing down. We will not be seeing these massive outbreaks they way we’re seeing now.” Jha said. “Once you get to 40 or 50 percent vaccination, it’s going to feel totally different.”

Jha said that by the beginning of spring, parts of the United States might be in a position to reopen more workplaces. In late spring or summer, he said, indoor dining and other indoor leisure activities could be safe and comfortable. Higher-risk activities in crowded spaces like indoor concert venues might take longer, perhaps upward of a year.

Though experts varied on how quickly these things might happen, with some saying it could be summer before a shift toward normalcy begins, all agreed on the rough outline: As vaccination increases, major outbreaks will decrease in size and frequency and restrictions will gradually lift.

Our new normal will not be without its reminders of the pandemic, experts said. A high level of public health surveillance will be crucial to monitoring and preventing outbreaks. Taking a rapid test before eating out or starting work could well be part of our new normal. And because COVID-19 could recede at different times in different countries based on vaccine availability, travel screening and some level of international border restrictions could remain in place for years to come.

“If you haven’t gotten deaths down to zero and eradicated the virus, then you can potentially have outbreaks take off again,” said Zoë McLaren, an associate professor of public policy at the University of Maryland, Baltimore County whose research focuses on public health. “But as long as we have enough precautions that we can catch any outbreak, then we can resume normal activities.”

Vaccines alone are not guaranteed to deliver the United States to a new normal, experts warned. The coming months will be a crucial time for developing an exit strategy for life post-pandemic — and for minimizing further unnecessary deaths.

Lines of cars carried people to get tested for COVID-19 in the parking lot of TJX Companies Inc. in Framingham on Nov. 17. Suzanne Kreiter/Globe staff

Experts said the federal government should plan and fund vaccine distribution, launch campaigns to encourage vaccination, and invest in more widespread testing. Social distancing restrictions, including mask-wearing and limited group sizes, also need to be encouraged, they said.

“We have every reason to be hopeful that a vaccine plus coordinated federal leadership . . . can get us to a new normal relatively quickly,” said Sam Scarpino, a Northeastern University epidemiologist. “If we do not take non-pharmaceutical interventions . . waiting on a vaccine alone will probably take a year or more. But if you imagine taking those effective vaccines and layering them with the tools we have, there’s no reason we couldn’t kind of enter a new normal exiting the winter.”

Ordinary people also have a part to play in speeding along the pandemic’s end, experts said. They encouraged both caution and optimism: Hunker down now with the knowledge that safe gatherings may be only a few months away.

“We want to step up the social distancing, mask-wearing, and testing precautions that we take because the end is in sight,” McLaren said. “If we can prevent infections over the next few months, those will be clearly lives saved.”