AUSTIN — With more than 7.4 million Texans having received at least one dose of a coronavirus vaccine and millions more previously infected and carrying antibodies, herd immunity could be on the horizon.
But how soon is anybody's guess.
Estimates vary on what percent of the population must be protected from the virus to reach herd immunity, the point at which each infected person transmits the disease to an average of fewer than one other person, and it starts to die out.
Dr. Anthony Fauci, the nation's top infectious disease expert, has said the number could be as high as 85%.
Dr. John Zerwas, a top medical adviser to Gov. Greg Abbott and vice chancellor for the University of Texas Health System, told the American-Statesman that even if the goal is 70%, "we've got a ways to go."
Zerwas attributes the decline in cases and hospitalizations, two key indicators of the pandemic's intensity, in part to the rise in vaccinations. Other health experts aren't too sure.
"I definitely attribute (the decline in cases) to the combined effect of immunity from natural disease and vaccination," Zerwas said, adding that older, higher risk residents have received a vaccine at even higher rates. More than six in 10 Texas seniors have received at least one dose, according to the latest data from the Texas Department of State Health Services.
"My sense is the impact of the current level of vaccinations or immunity that we have in that at-risk population is definitely something that's contributing to the improvement in the numbers."
Up to 13 million Texans may have natural immunity through previously having been infected, Zerwas said, a number he based on CDC guidance. The true number of infected people is thought to be many times higher than what's been reported through testing. More than 2.4 million people in Texas have tested positive for the coronavirus
"We can take a pretty good bit of confidence that the natural immunity is good protection immunity against the disease," Zerwas said. "If you combine that with the number of people who have gotten some amount of vaccine, plus those that are naturally immune at this point, you get up to a pretty high rate."
Hundreds of people with appointments wait in line to receive a COVID-19 vaccine at Gregory Gymnasium at the University of Texas on March 1. Starting last Monday, all Texans 16 and older are eligible to be vaccinated.
But Texas also has a large youth population, which could affect how quickly the state reaches herd immunity.
Zerwas estimated that 21 million people in Texas are 18 or older, making them eligible for all three authorized COVID-19 vaccines. The Pfizer vaccine is the only COVID-19 vaccine available for those 16 and older.
People who have previously contracted the virus should still get a coronavirus vaccine, according to federal health guidance.
"In the strictest sense, you have to take the whole population of Texas," to determine herd immunity, Zerwas said, adding that between 8 to 9 million Texans are under 18. "It's hard to say, but I like to tell people that I think the summer will be a lot more normal. By the end of April, I think we're going to see a lot more normalcy to our lives."
Travis County's interim Health Authority Dr. Mark Escott also offered an optimistic outlook in a Wednesday news conference, estimating that by mid-April, the Austin area could see coronavirus restrictions relaxed further if the public continues to follow safety protocols like wearing face coverings and keeping social distance.
With vaccinations continuing, Escott said Central Texas could reach herd immunity by summer among those in earlier vaccination eligibility groups: health care workers, first responders, teachers, child care workers, those 50 and older and those 60 and older with underlying conditions.
"I think for adults, we can reach herd immunity in those sub-groups in the summer," Escott said.
He did not mention when the entire population could reach herd immunity.
Starting last Monday, all Texans 16 and older are eligible to receive a coronavirus vaccine.
Even as some states are seeing an uptick in cases amid emerging variants and as national health experts warn of a fourth wave, case numbers in Texas continue to ebb.
It's a massive shift from the picture three months ago, when hospitalizations and case numbers were rising quickly and intensive care beds were in short supply across the state.
Since a pandemic peak in mid-January, cases have dropped to below 3,000 per day, levels not seen since early June. The seven-day rolling positivity rate also has hovered around 5.5% in recent days, the lowest in a year.