March 10 marks a year since Dallas County reported its first case of what eventually became known as COVID-19. During the ensuing months, much has been discussed about herd immunity.
But what is it?
“‘Herd immunity’, also known as ‘population immunity’, is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection,” the World Health Organization explains.
With the high death toll and rate of hospitalizations, most if not all infectious disease experts would like to achieve herd immunity by getting the majority of the population vaccinated for COVID-19, instead of allowing the disease to progress through populations, overwhelming hospitals and depleting supplies and equipment.
In short, it’s easier to manage finite resources if you can immunize versus letting the virus play out.
Herd immunity also protects those most vulnerable to the virus.
“One of the aims with working towards herd immunity is to keep vulnerable groups who cannot get vaccinated (e.g. due to health conditions like allergic reactions to the vaccine) safe and protected from the disease,” said the WHO. “Attempts to reach ‘herd immunity’ through exposing people to a virus are scientifically problematic and unethical. Letting COVID-19 spread through populations, of any age or health status will lead to unnecessary infections, suffering and death.”
And now Dallas County has herd immunity in its sights. Last month, Parkland Center for Clinical Innovation – for the first time since this all started – announced that it appears that the county might just reach herd immunity by the end of June.
PCCI forecasted at the end of February that the county was on pace to have 80% of its residents at levels of herd immunity by mid-summer.
But did Gov. Greg Abbott’s announcement that he would not only reopen businesses at 100% capacity but also rescind a mask mandate change that trajectory?
In a word, no. But in more words, no, but that doesn’t mean we should stop wearing masks and practicing social distancing, and all the other things that help keep the infection rate lower, said PCCI CEO Steve Miff.
“The latest policy announcements and developments are not anticipated to significantly change the herd immunity projections at this time,” said Miff. “We have modeled increases in infection rates post holidays and gathering events such as Easter and spring break and taken into account the research on new variants known to date.
“Infections might accelerate in some areas within certain demographics, but they can be balanced by the accelerated timeframe for the availability of vaccines and pace of vaccinations.”
Miff echoed what other public health experts have said – vaccinations are the best way to get to herd immunity.
“We will get to herd immunity through vaccinations and while the path to herd immunity is in sight, now is not the time to let our guard down,” he said. “We will continue to closely track all data and update the models as new information emerges. “
Miff also had some good news – vaccination efforts have inched the county even closer to herd immunity.
“Despite the impact of the winter storm, over the last week the confirmed and presumed recovered population in Dallas County increased to 36% (935,921 people) and over 11% (295,374) of the total population in Dallas County has been vaccinated,” he said. “Accounting for the population overlap, efficacy of vaccines and other factors, the path to herd immunity increased to 45.5%.”
For reference, at Feb. 22, PCCI’s analysis indicated that the county had reached 44% of the 2.6 million adult residents of Dallas County as either recovered from COVID-19 or in the process of receiving their full COVID-19 vaccine. That includes 922,460 COVID-19 confirmed and presumed infected and recovered, and 270,642 residents who have received their first (154,766) and second (115,875) vaccine shot.
Recently, National Institute of Allergy and Infectious Diseases director Dr. Anthony Fauci, as well as the WHO, said that herd immunity could potentially be reached by as little as 70% of the population gaining immunity, with Fauci giving a range of 70-90%, and the WHO giving a range of 60-70%.
In other news:
- After 25 new deaths were reported by Dallas County Tuesday, the death toll attributable to COVID-19 eclipsed 3,000 since the pandemic started, county officials said. Tuesday also saw 526 new cases.
- President Joe Biden said Tuesday that he expects that there will be enough vaccine by May for every adult that wants to be immunized to do so.
- Texas will release information on the next group eligible for the vaccine this month – and it is expected to include more essential workforce, including school employees.