According to experts, persistent skepticism about the COVID-19 vaccine and increased variants means that herd immunity is unlikely. A return to normalcy is still possible by vaccinating the most vulnerable, but the continued prevalence of COVID-19 variants is an obstacle to normalcy. How do we measure the variants’ spread and our own population’s immunity, and how can we make progress in Dallas?
The focus on herd immunity has been whittled away over the past few months, as health experts communicate that emphasizing a specific percentage of immunity isn’t helpful. As a population grows its immunity, life will gradually return to normal. Putting a bullseye on a specific number is both unlikely and not practical. Additionally, focusing on the entire population may not be as helpful as understanding how our smaller social and work circles are impacted. If everyone at a small office has immunity, that is more important than what the entire city or state is doing.
But that doesn’t mean public health efforts are slowing their efforts to continue vaccinations. Taking vaccines into hesitant or hard-to-reach populations, working directly with employers for pop-up vaccination sites, and other education efforts are still part of the plan. “I’m very optimistic, having seen the impact that the vaccination can have in a population,” says Dr. James Cutrell, the program director of the infectious diseases fellowship program at UT Southwestern.
Besides personal health, continued vaccination efforts help reduce the spread and growth of COVID-19 variants. One needs to look no further than India to see the importance of containing variants. The virus is running rampant in the country, with the country accounting for 50 percent of total cases and 30 percent of deaths. Most of that spread is thought to be from the variant of COVID-19 detected there in February. The World Health Organization classified the variant as a “variant of concern” and the U.K. and Brazil variants. On May 20, UT Southwestern sequencing found its first cases on the Indian variant in North Texas, making it the second-most prominent behind the U.K. variant.
Cloer to home, UT Southwestern found in April that the U.K. variant of COVID-19 had become the dominant version of the virus here in North Texas, with the California, New York, and Brazil variants also present. The Brazil variant is worrying, as it is more contagious and less susceptible to antibodies. The U.K. variant is around 50 to 60 percent more contagious but responds well to vaccines and monoclonal antibodies.
The regular COVID-19 tests can’t detect the variants but require genomic sequencing of the person detected. For months, UT Southwestern has been sequencing 20-30 samples per week to measure the growth of variants. Over half of those who were sequenced was the U.K. variant in UTSW’s testing. “We’re in a much better place than we were six months ago or eight months ago in terms of being able to detect if one of the current variances is starting to take off or if a new variant that hasn’t been identified starts to increase,” Cutrell says.
Nationwide, sequencing has ramped up as well. The CDC can sequence 30,000 viruses per week, and Texas has submitted the second-most viruses of any state in the country. But the spread of the virus elsewhere gives opportunities for it to mutate and create new variants that could be resistant to vaccines and treatments, though there hasn’t been evidence of a version like that. The challenge for public officials now is balancing domestic efforts with international threats.
“What we don’t want to happen is a new variant that is more resistant to our treatments that spreads into other countries that have gained control of the pandemic, and then we start to lose ground because of the interconnectedness of the global community,” Cutrell says. “The challenge we have to figure out is how we continue to encourage the vaccine efforts here while also reprioritizing to other parts of the world where they’re sorely needed so that we can bring the whole global pandemic under control.”
