How close is the state to herd immunity as COVID-19 vaccination in Texas accelerates? | Nation / World

Estimates depend on what percentage of the population must be protected from the virus to reach herd immunity, when each infected person, on average, infects less than one other person with the disease and begins to disappear. Varies.

Dr. Anthony Fauci, the nation’s top infectious disease expert, said the number could be as high as 85%.

Dr. John Zelwas, Governor Greg Abbott’s Chief Medical Advisor and Deputy Prime Minister of the University of Texas Health System, said, “We have a way,” even with a goal of 70%. Told to.

Zerwas believes that the two key indicators of pandemic intensity, the decrease in cases and hospitalizations, are partly due to the increase in vaccination. Other health professionals are less confident.

“I’m definitely (decreasing cases) due to the combined effects of immunization and vaccination from natural illnesses,” said Zelwas, who said that older, higher-risk residents are vaccinated at an even higher rate. He added that he was doing it. According to the latest data from the Texas Department of Health, more than 6 out of 10 elderly people in Texas take at least one dose.

“In my sense, the impact of current vaccination or immunity levels in the at-risk population is undoubtedly contributing to the improvement in numbers.”

According to Zelwas, up to 13 million Texas people may have innate immunity from a previous infection, based on CDC guidance. The actual number of infected people is believed to be many times higher than the number reported in the test.More than 2.4 million people in Texas test positive for coronavirus

“We can be quite confident that innate immunity is a good protective immunity against disease,” Zerwas said. “If you combine that with the number of people who have been vaccinated to some extent, plus the number of people who are naturally immune at this point, it’s a fairly high percentage.”

Hundreds of people with reservations are waiting in line to receive the COVID-19 vaccine at the Gregory Gymnasium at the University of Texas on March 1. Starting last Monday, all Texas people over the age of 16 are eligible for vaccination.

However, Texas has a large youth population, which can affect the time it takes for the state to reach herd immunity.

Zerwas estimates that 21 million people in Texas are 18 years of age or older and are eligible for all three licensed COVID-19 vaccines. The Pfizer vaccine is the only COVID-19 vaccine available for people over the age of 16.

According to federal health guidance, people who have previously been infected with the virus should be vaccinated with the coronavirus vaccine.

“Strictly speaking, we need to determine herd immunity for the entire Texas population,” Zelwas added, adding that 8-9 million Texas people are under the age of 18. I think summer will be more normal. By the end of April, I think our lives will be more normal. “

Dr. Mark Escott, Interim Health Authority in Travis County, also showed optimism at a press conference Wednesday, if by mid-April the public would follow safety protocols such as wearing and maintaining face coverings. , Estimates that coronavirus restrictions may be further relaxed in the Austin region. Social distance.

As vaccination continues, Escott said Central Texas is a group of people in the early vaccination qualification group: healthcare workers, first responders, teachers, childcare workers, over 50 and over 60 with underlying illness. He said that mass immunity could be reached among people by the summer.

“I think adults can reach herd immunity in those subgroups in the summer,” Escott said.

He did not mention when the entire population could reach group immunity.

Starting last Monday, all Texas people over the age of 16 are eligible for the coronavirus vaccine.

In some states, the number of cases has increased with the emergence of variants, and the number of cases in Texas continues to decline, despite national health professionals warning about the fourth wave. ..

This is a major change from the situation three months ago, when hospitalizations and cases increased rapidly and there was a shortage of intensive care units throughout the state.

Since the peak of the pandemic in mid-January, the number of cases has decreased to less than 3,000 per day and has not been seen since early June. The 7-day rolling positive rate has recently been around 5.5%, the lowest in a year.

Still, some health professionals say vaccination is not the main driver of reduced cases and hospitalizations.

As of Wednesday, Jungsik Noh, an assistant professor at UT Southwestern in Lyda Hill Bioinformatics, estimated that 25% of Texas people were infected with the virus. Noh, who studied the undercounting of COVID-19 cases, said his estimates did not consider vaccination and were based on daily reported cases and deaths.

“I don’t think this decline is primarily due to increased vaccination rates or the number of people who previously had Covid,” Noh said. “Vaccination rates and cumulative incidence are undoubtedly factors that slow spread, but they are not large enough at this time.”

Noh also estimated that about 44.5% of Texas people “have some immunity from previous infections or vaccinations.”

“In my opinion, no one has a clear idea of ​​the threshold for herd immunity,” Noh said. “In my view, 44.5% doesn’t seem to be enough yet.”

Lauren Ancel Meyers, director of the UTCOVID-19 Modeling Consortium, attributed this decline to behavioral and policy changes at the regional level.

“We still don’t think it can be explicitly attributed to vaccination,” she said. “Ultimately, the effects of the vaccine will be seen. At some point, mitigation of the measures will reduce the level of infection, but it is not there yet.”

According to Myers, immunization rates are higher in some parts of Texas and in some communities than in others.

Myers’ team recently investigated the potential impact of spring break gatherings and more contagious coronavirus variants as Abbott ended state-wide coronavirus restrictions, including mask obligations.

Predictions would be that if face mask orders remained the same and travel was low until spring break, the number of cases would have been even lower than before. In Austin, the number of cases was declining rapidly, but has recently peaked. According to Myers, it shows that Texas isn’t working as expected.

“It’s also evidence that our actions are still actually promoting the infection, and we’re still far from enough vaccines to control the virus,” Myers said.

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