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To beat coronavirus, herd immunity is the goal. Can Florida get there?

Demand for vaccines is slowing, even as more people become eligible. That could prolong the pandemic.
State canvassers Cynthia Hollinger, 64, standing on right, and Sunni Schappacher, 67, talk with a family as they work to re-register them in a state database for a coronavirus vaccine on their front porch Wednesday in Brandon. From left is Curtis Lanier, 65, holding his 2-year-old daughter Lena Jean, along with his father-in-law Paul Bedat, 76. The canvassers are going door-to-door to speak with people who are hesitant about the vaccines. It's part of Florida's effort to reach herd immunity.
State canvassers Cynthia Hollinger, 64, standing on right, and Sunni Schappacher, 67, talk with a family as they work to re-register them in a state database for a coronavirus vaccine on their front porch Wednesday in Brandon. From left is Curtis Lanier, 65, holding his 2-year-old daughter Lena Jean, along with his father-in-law Paul Bedat, 76. The canvassers are going door-to-door to speak with people who are hesitant about the vaccines. It's part of Florida's effort to reach herd immunity. [ DIRK SHADD | Times ]
Published Apr. 22
Updated Apr. 24

The rollout of coronavirus vaccines in Florida was heralded as a light at the end of the tunnel for a pandemic that has upended normalcy and killed 35,000 people in the Sunshine State alone. Now comes the question of just how long the tunnel is.

Across Tampa Bay, officials are seeing slowdowns in the number of people lining up for doses. One site in Plant City averaged 200 to 300 shots a day during the first full week of April, though managers there had planned for a daily average of 1,000.

“We have a lot of vaccines out there all over the place, but people aren’t getting it,” said Kevin Watler, a spokesman for the Florida Department of Health in Hillsborough County. “How fast we can resume to normal really lies with people who are choosing not to get vaccinated.”

Watler is talking about herd immunity, the point where enough people are immunized to block transmission of a virus. It’s the final milestone before the pandemic can end.

Getting there will depend on many factors, experts say, including how many people acquire immunity through vaccination or infection, how long each type of immunity lasts and human behavior.

More than 45 percent of eligible Floridians have received at least one dose of a coronavirus vaccine, and surveys show that hesitancy about the vaccines has been decreasing. After a rocky start to Florida’s vaccine rollout, residents can now turn to multiple providers, even with the pause in the single-dose Johnson & Johnson vaccine that ended Friday. And doses, which are free of charge, are fairly easy to obtain for most people.

Still, a significant number of people don’t plan to get vaccinated, according to surveys. And so far, children under 16, who make up nearly 20 percent of the population, aren’t eligible. That leaves roughly 10 million eligible Floridians over 16 who have yet to roll up their sleeve.

Large numbers of people without immunity makes a return to pre-pandemic life more risky, experts say. Infection could spread through non-immunized communities, which would offer a greater chance for the virus to mutate and become harder to control.

The result: more cases and a lengthening of the pandemic.

Already, a fourth spike of coronavirus cases has been fueled by variants that are more transmissible and have become dominant in the U.S., particularly in Florida.

“We are in a race to get people vaccinated as soon as possible, because we’re just starting the next surge,” said Marissa Levine, a professor of public health at the University of South Florida. “We don’t know what it will look like, but it has the potential to cause preventable suffering and death.”

When might we reach herd immunity?

Between 60 and 85 percent of people need to be immune to the coronavirus to reach herd immunity, based on experts’ varying estimates.

That number becomes even more difficult to hit considering that all children aren’t eligible for shots yet. Without them, the percentage of immune adults would need to be even higher, said Josh Michaud, associate director of global health policy at Kaiser Family Foundation.

About 25 to 30 percent of American adults have contracted COVID-19 at some point in the pandemic, which gave them an estimated six to nine months of natural immunity, Michaud said. Vaccination, meanwhile, is thought to provide one to three years of immunity.

That means those infected in early 2020 have likely run out of antibodies to fight COVID-19, although some may have since been vaccinated, as directed by health experts. The overlap makes it difficult to know just how close we are to herd immunity, Michaud said.

In Hillsborough County, about 20 percent of adults have natural antibodies against COVID-19, according to a March study by Moffitt Cancer Center led by Dr. Anna Giuliano, founding director of the Center for Immunization and Infection Research in Cancer.

The only realistic way the state can get close to reaching herd immunity is through large numbers of people choosing to get vaccinated, Giuliano said. Some other experts disagree, saying it can be achieved over time as the virus continues to spread. But most agree that reaching it with vaccination will be less painful.

“At some point, we will reach herd immunity, it’s just at what cost,” said Dr. Edgar Sanchez, an infectious disease specialist with Orlando Health. Depending primarily on natural immunity, he said, would mean “scores of more deaths.”

Ramon Camacho, 38, left, talks with state canvassers Evelyn Escalante, 49, and Jack Alvarez, 49, as they reregister him in a state database for a coronavirus vaccine on Terrace Drive in Brandon. Camacho is a worker renovating a house on the street.
Ramon Camacho, 38, left, talks with state canvassers Evelyn Escalante, 49, and Jack Alvarez, 49, as they reregister him in a state database for a coronavirus vaccine on Terrace Drive in Brandon. Camacho is a worker renovating a house on the street. [ DIRK SHADD | Times ]

Michaud, from Kaiser, said he isn’t confident that herd immunity is just around the corner for the U.S., citing lower demand for shots. He called it “difficult … if not impossible” to get there in the next few months.

As of April 21, more than 26 percent of Americans were fully vaccinated. Combine that with an optimistic 20 percent of people with natural defenses, and it’s still not enough to meet even the lowest estimate of immunity to eradicate the virus.

Edwin Michael, a professor of epidemiology at USF who is modeling predictions of the coronavirus in Florida, estimates that the state will reach herd immunity by December if the vaccination rate and current social measures stay the same.

At double the speed, the state would reach it in July, he estimates. At three times the speed, it would reach it in June, he said. But much could change those estimates, including human behavior and the current — and future — introductions of new coronavirus variants.

The state could slip in and out of herd immunity or see the threshold needed for it rise as some people who were inoculated early on run out of immunity and require booster shots, or as more contagious strains emerge.

“This is now a race,” Michael said, “between the rate of vaccination, the social measures in place and the new wave of coronavirus cases.”

Softening demand for shots

Vaccine providers in Florida say they have doses for people who want them. But in many cases, available appointments are now taking longer to get filled, even as millions more people have recently become eligible.

That’s frustrating to those working in public health.

“We fought to get the vaccine, and we got the vaccine,” said Watler, the health department spokesman in Hillsborough County, where demand has slowed.

Last Monday, Pasco County’s health department said only 150 out of 900 vaccine appointments were taken. The health departments in Hernando and Pinellas counties are also seeing unfilled appointments.

Statewide, tens of thousands are getting vaccinated every day, state data shows. Florida’s rate of vaccination is about on par with the nationwide average, according to the U.S. Centers for Disease Control and Prevention. But it’s still not going as quickly as some had hoped.

The number of daily vaccinations for residents 65 and older, who have been eligible for shots since December, has been slowing since late March. That’s likely because about 80 percent of people in that age group already have been at least partially vaccinated.

But vaccinations among people ages 45 to 54, some of whom have been eligible for about three weeks, also have been trending down on a daily basis so far in April. About 40 percent of people in that age group had gotten at least one dose as of Wednesday.

Vaccinations among people ages 16 to 44 had been rising but have slowed in recent days. So far, about a quarter of people in that age group have gotten at least one dose.

The race against variants

The more-transmissible B.1.1.7 variant has become the dominant strain of the coronavirus in the country — and Florida has the most cases of any state, data from the Centers for Disease Control and Prevention shows.

The introduction of vaccines themselves could drive the mutation of variants, thanks to what is known as “selection pressure” causing the virus to adapt to survive, said Michael, the USF professor.

The mutations found so far, he said, have spread “very fast.”

Hillsborough County has seen the effects of the B.1.1.7 variant as COVID-19 admissions at Tampa General Hospital have swelled over the last month, said emergency department director Dr. Jason Wilson. Hardly any of the patients who tested positive had been vaccinated, he said.

“The rise in cases is going up faster than the people getting vaccinated, and we want the opposite,” Wilson said.

He and Dr. Kami Kim, an internal medicine physician at Tampa General, say the virus has been spreading more among young people, largely because fewer of them have gotten the vaccine, and they may be more likely to eschew social distancing and other safety measures.

Wilson said that, based on conversations he’s had with patients, younger Floridians are less likely to get the shot than older people because they have repeatedly heard they’re less at risk for severe complications from the disease.

But even if those unvaccinated people don’t get severely ill, experts say, they could still spread COVID-19, giving the virus opportunities to mutate into more-aggressive strains.

Who isn’t getting shots

A growing share of Americans say they are willing to get the vaccine, according to a March poll by the Kaiser foundation. But vaccine hesitancy — and outright resistance — remains.

A steady 13 percent of people have said since December that they will “definitely not” be vaccinated, the poll found. Most identified as Republican or white evangelicals, with half of Republican respondents saying they feared being forced to get a vaccine against their will.

The poll also found that 17 percent of Americans are taking a wait-and-see approach, a smaller percentage than in earlier surveys. Those respondents worried about side effects, that they may be worse than the virus itself, as well as wanting to see more safety data over time.

While hesitancy among Black and Hispanic people has shrunk from earlier polling, those groups still expressed the most concern about not being able to get a vaccine from a trusted source or said they would have difficulty getting to a vaccine site.

Thirty-three percent of poll respondents did not know where to get a shot, and 46 percent weren’t sure about their eligibility.

Some of the same themes Kaiser found are reflected in Tampa Bay, according to the most recent survey by the Tampa Bay Partnership, which has spent more than a year tracking how local residents feel about the pandemic.

Related: Tampa Bay's on the right COVID-19 path, survey says, but vaccine doubts remain

Three-quarters of respondents said they were more likely to get a vaccine in March, an increase from 67 percent in January. Many still cited concerns about side effects and said they needed more information.

More than 40 percent of Black residents said they were not likely to be vaccinated, as did 36 percent of residents ages 18 to 34.

Finding solutions

Efforts need to focus on reaching people who are hesitant or don’t know where to get vaccinated, experts say.

“It’s no longer enough to say, come and get your doses,” said Jason Salemi, a professor of epidemiology at the University of South Florida. “We have to tackle this problem.”

Wilson, the Tampa General doctor, has been talking to one of his regular patients, a Black person with sickle cell disease, about vaccination for four months.

The patient has yet to agree, he said. But they’ve made progress with longer conversations and more nuanced and focused questions about the vaccines.

“This is a long-term, consistent and persistent conversation about some pretty complex science,” Wilson said.

That same level of care and understanding needs to happen on a larger level, Wilson and other experts say. Many communities are still lacking information, access and trust in the vaccines — and the recent pause on those by Johnson & Johnson has only added to their hesitancy.

The Florida Division of Emergency Management has hired 2,900 canvassers to knock on doors in four major cities, including Tampa, where the state and federal governments are running mass vaccination sites. They’ve visited more than 510,000 homes providing information and helping people sign up for shots, a division spokeswoman said.

Teams have talked to about 43,000 people in Hillsborough County neighborhoods, with about 11,000 agreeing to register for vaccines, the state said. Another 12,000 said they had already received shots, but about half — 21,000 — said they were not interested.

Pairs of canvassers circled a Brandon neighborhood on Wednesday as registered nurse Stacey Gedeon stood by, ready to answer any clinical questions. People most often ask about side effects, she said.

Her team interacts with about 300 people a day, with an average of 25 agreeing to register for shots. Earlier in the vaccine rollout, about 50 a day would agree to sign up, but the number has dipped as more people have been vaccinated. She saw a lull after the Johnson & Johnson pause, too, she said.

Registered nurse Stacey Gedeon, right, said state canvassers saw a dip in vaccine registrations after officials announced they were pausing administration of the Johnson & Johnson vaccine recently. She is accompanied by Kinyatta Moore, a team leader for the canvassers.
Registered nurse Stacey Gedeon, right, said state canvassers saw a dip in vaccine registrations after officials announced they were pausing administration of the Johnson & Johnson vaccine recently. She is accompanied by Kinyatta Moore, a team leader for the canvassers. [ DIRK SHADD | Times ]

“My team is trained not to pressure people,” Gedeon said. “We just give them the facts and information. They have to make a decision themselves.”

The state has moved on other fronts, too, like locating vaccine clinics at places of worship and in rural communities. The Department of Health is working with Florida A&M University on a public service campaign aimed largely at Black residents in certain parts of the state.

Counties are bringing vaccines to underserved areas and joining with community and faith groups to get the word out. Hillsborough County, for example, recently bused residents of a mobile home park to get shots, and it’s hosted multiple social media events so residents could ask experts questions.

But Kim said a more coordinated plan and better collaboration among all stakeholders is needed to reach the numbers of people required for herd immunity. She added that the state’s supply of doses to vaccine providers has not been consistent or predictable enough for optimal and equitable distribution.

Related: While more governors publicly vaccinated, DeSantis mum on his shot

As Florida and the U.S. continue to work toward the goal of herd immunity, experts beg people to be patient and not abandon social distancing and other guidelines too quickly.

That could be a struggle, particularly in Florida, which has been open for months.

Dr. Tom Unnasch, a professor of public health and biology at USF, said a move by Gov. Ron DeSantis to preclude businesses from requiring evidence of vaccinations from customers could hurt efforts to contain the virus before enough people have immunity.

Related: DeSantis: Businesses requiring vaccine passports can't get state money

Unnasch said incentives to get the vaccine, such as employers requiring them or businesses offering deals, could help prod some who are reluctant.

“None of us are really protected until we’re all protected,” Unnasch said.

Staff Writer Langston Taylor contributed to this report.

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