Vaccine

Susan Valadez watches a Texas Department of State Health Services advertisement encouraging people to get the COVID-19 vaccine before she enters a Walmart in Fort Worth on April 30.

Only five months after the first COVID-19 vaccine was approved for emergency use, the shots are readily available to just about anyone who wants them.

Now the biggest obstacle to returning to normal will be changing the minds of millions of people who don’t want them.

Health officials have moved beyond the early, frantic effort to protect the most vulnerable to focus on the long, hard push toward herd immunity — the indirect protection a population gets when enough people have immunity to a virus to stall the rate of transmission.

But achieving that goal through vaccination rather than widespread infection may prove to be among the toughest challenges of the pandemic.

Here’s how North Texas’ four largest counties plan to hit herd immunity, and what might happen if it isn’t reached.

What progress has been made in reaching herd immunity?

Herd immunity doesn’t necessarily mean a virus is gone for good. In communities with high levels of immunity, a disease will peter out but infections are still possible. The measles and mumps, for example, still occur even though most communities have herd immunity against them.

With COVID-19, health experts don’t know exactly how many people need to have immunity to achieve herd immunity. A number of factors — including the emergence of variants and the difficulties in estimating the number of people who had COVID-19 in the past but were never tested — make the numbers tough to calculate.

In January, officials with the Centers for Disease Control and Prevention estimated 70% to 75% of people need to be vaccinated — a number that could jump as high as 85% if other variants of the virus become dominant.

Other health experts have generally agreed that the benefits of herd immunity kick in when at least 70% of a population has immunity.

In Dallas County, health officials have estimated 80% of residents need immunity, either through vaccination or recovery from the virus, for the community to be protected.

About 65% of residents are immune to COVID-19, according to the Parkland Center for Clinical Innovation, which has tracked COVID-19 data for the county throughout the pandemic.

Twelve ZIP codes — 75082, 75159, 75182, 75201, 75202, 75204, 75207, 75208, 75225, 75235, 75247 and 75251 — have passed the 80% threshold, said Steve Miff, president and CEO of the center.

Although that represents significant progress, the county is beginning to struggle with slowing vaccine demand and is lagging national vaccination rates, Miff said. The county had been progressing toward the 80% threshold by 3 percentage points per week, a rate that has since slowed to about 2% a week and has led the team to push the county’s herd immunity timeline from mid-June to late June or July.

The major hurdle before reaching that finish line isn’t the supply of vaccines — many places offer same- or next-day appointments and shots are increasingly available at a wider variety of providers.

Most people who were eager to get shots quickly have done so. Many of the people who have not been immunized have had a hard time getting to providers or are suspicious of the vaccines, said Steve Miff, president and CEO of the center.

To help get shots to those two groups, the center is working to set up pop-up clinics where vaccination rates haven’t been as high.

“We need to continue to make it easy for people to say yes,” Miff said. “We ran that analysis, we’ve identified the top neighborhoods that have the biggest unvaccinated populations. .... Let’s bring the resources closer to where people are.”

The Parkland Center for Clinical Innovation team is also working to secure financing for a large-scale study of vaccine hesitancy. The study, in partnership with other organizations, will help researchers determine how people make decisions about vaccination and who influences them, so providers can better reach the ones who are hesitant.

Dr. Philip Huang, director of Dallas County’s health department, said officials are also counting on the Pfizer-BioNTech vaccine being opened up to people 12 and older to help boost immunity numbers. The shot was initially only approved for those 16 and up, but on May 10, the Food and Drug Administration expanded its use to kids as young as 12.

Huang said the county already had been preparing to vaccinate younger people. Anyone is encouraged to register with the county regardless of age so they can be ready when the shots are available. Also, health officials have been working with school districts to set up parental permission processes and the county is planning to bus groups of kids to Fair Park, the county’s mass vaccination site, to get the shots.

Huang said the county also has set up informational events to counter vaccine myths and misinformation and is reaching out to various community leaders and institutions, like First Baptist Church in Dallas, to encourage them to promote vaccines. He said the city also plans to set up vaccine clinics in high-traffic places such as Galleria Dallas and NorthPark Center.

“I think it’s going to take all of these efforts,” he said. “There’s not a single magic bullet.”

Other counties take a similar approach

Other health departments in North Texas are also working to reach hard-to-reach populations. The general idea, experts said, is to make it as easy as possible for people to get shots.

In Tarrant County, about 38.6% of the population 16 and older has been fully vaccinated, according to state data. One of the county’s mass clinics at the AT&T Center shut down last month because of a decline in demand, and health officials are turning their efforts to pop-up sites.

Experts there generally think about 70% or more of residents need to be vaccinated for the area to reach herd immunity, said Dr. Teresa Wagner, an assistant professor in the school of health professions at the University of North Texas Health Science Center.

The health science center partners with the county to help administer vaccines and has set up four “boutique” vaccine sites in Saginaw, Fort Worth’s Stop Six neighborhood, at Ridgmar Mall and the University of Texas at Arlington, Wagner said.

“We know that when it’s convenient, free and easy that people are more likely to go get it,” she said. “They also have to have confidence in the vaccine safety and trust the delivery system. At that point, we look to trusted messengers, so people in those communities who typically are community leaders. In one area we’re using barbers, salons and faith leaders to reach out to the communities because these are the people that those communities trust.”

At a May 4 meeting of the Tarrant County Commissioners Court, a representative with the health science center said that door hangers, flyers and yard signs are being distributed in areas with low vaccine rates and that direct mailers are being sent to about 250,000 homes later this month.

The center is also planning to transition from the four boutique sites, which will run six to eight weeks each, to operating purely pop-up sites, which will operate two to five days each.

In Collin County, about 49.9% of the population over 16 is fully vaccinated, according to the state. The county partners with Curative Medical Associates to distribute vaccines, and is also moving away from mass vaccination sites.

Spokesman Darrell Willis said that the county doesn’t have an estimate of how many people need to get a shot to reach herd immunity but that the goal is to try to vaccinate as many people as possible.

One of the county’s larger sites, at John Clark Stadium in Plano, will be closing soon so that Plano ISD can use the grounds for graduation ceremonies. Willis said Curative hasn’t given the county an indication of if, or when, it will set up there again.

He said Curative plans to open a smaller, two-lane vaccination site at McKinney ISD Stadium, which they hope to have ready by May 24. Curative is also looking at setting up small vaccine “kiosks” in some parking lots.

To meet the demand where it is, Collin County Health Care Services is exploring partnerships with home health-care programs and organizations such as Meals on Wheels and is also starting “mobile strike teams” that will be available to visit individuals or groups to administer shots, he said.

“The main individuals that we’d be targeting with that for vaccinations would be home-bound people, individuals that can’t really move well,” he said, adding that the county aims to have the team operating by mid-June. “Secondary would be like if there was a large church group that wanted to get all their vaccinations done at once.”

Dr. Matt Richardson, director of Denton County’s health department, said officials have “gone to great lengths” to get vaccines to populations that face problems obtaining vaccines. The county has expanded hours to accommodate people who can’t take off work and implemented programs to vaccinate home-bound and homeless individuals, he said.

About 44.4% of the population 16 and over in Denton County is fully vaccinated, according to state data. Richardson said he expects herd immunity to start kicking in when about 70% of the population is immune.

But how and when the county gets there is largely dependent on “getting to those folks who are on the fence.”

“About three weeks ago, we sort of crossed this almost imaginary line of where the supply curve and the demand curve met, where the supply was increasing and demand was decreasing,” he said. “We’re now in the education and the influence mode, whereas before we were simply in the logistics and appointments and distribution mode … and that’s a lot more difficult.”

Richardson said he anticipates operations at Texas Motor Speedway, the county’s mass vaccination site, to stop in mid-May. The site’s last clinic was scheduled for Friday, and then the county plans to shift to partnering with community organizations to administer shots beginning in late May.

“We are looking at sort of national trends and indicators of vulnerability, and we want to target that, and then obviously we are going to find pockets of under-vaccinated populations,” Richardson said.

What if we don’t reach herd immunity?

Health experts say a variety of factors make reaching herd immunity in the U.S. unlikely, or even impossible.

Now that other variants of the virus, some of which may be more contagious and more severe, are circulating, communities are racing the clock to get people vaccinated before they become dominant. And it’s still not known whether people who are immunized can spread COVID-19, which could significantly affect estimates.

It’s also unknown how long the vaccines, or recovery from a COVID-19 infection, provide protection. If people have to get vaccinated regularly, the level of immunity in a community can change over time. In the meantime, the protection against the virus depends on people following preventive measures such as wearing masks and social distancing.

It’s becoming more and more likely, health experts say, that COVID-19 becomes what’s known as an endemic virus, or a disease that regularly occurs within a population. In that case, the goal would be to get COVID-19 cases to a manageable level, where cases, hospitalizations and even deaths may still occur, but at much smaller rates.

“We may just have a consistent flow of cases at a certain population rate,” said George “Holt” Oliver, vice president of clinical informatics at the Parkland Center for Clinical Innovation. “In that sense, there’s enough immunity in the community to reduce the risk of hospitals being overwhelmed the way they were at the worst parts of the fall ... but the case rates are just going to continue on at low rates.”

Even without herd immunity, the benefits of the vaccine are still apparent.

“Despite several key factors that would have contributed to another peak — and that is the complete opening of the economy here locally, two sort of major gathering events, spring break and Easter and the other holidays, plus the emergence of the U.K. variant — … despite those three key things that typically contribute to significant numbers of cases and subsequent hospitalizations, etc., the cases have stayed relatively flat if not even have decreased,” Miff said. “Both on the hospital side as well as the infection side.”

Health experts said the benefits of the vaccine are starting to be seen most clearly among people 65 and older, who were among the first vaccinated.

But as older people gain more protection, hospitalizations have started increasing among young people, who have not been vaccinated at as high rates and are more likely to be hesitant about getting the shots.

Dallas County Judge Clay Jenkins has started warning about more serious cases being reported among younger residents.

“The pattern that we see is that the enthusiasm goes down with age,” Oliver said. “The biggest predictor is probably your internal risk-benefit analysis of ‘How sick do I think I’m going to get?’”

He said that if the trend of more severe cases occurring in young people continues, vaccination rates could rise again.

Health experts say everyone should get vaccinated regardless of perceived risk. People who are not as vulnerable to the virus are still “rolling the dice” and could be among the people who suffer serious illness or long-term side effects.

Oliver said that most people are universally “better off getting their immunity from the vaccine as opposed to the virus,” and that there are community-level benefits to vaccination as well.

“If you can stand up for your community, it may not be that much of a risk to you individually, but your friends, your family, people around you, they’ll all be protected by you,” he said. “It’s like jumping in a lake to save a drowning child.”

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