T Cells May Be Critical to Understanding Immunity to COVID-19
Since the COVID-19 pandemic began, researchers have focused on the antibodies that recovered patients develop in order to track the spread of the disease. However, scientists now believe that antibodies may not be the key to providing immunity from COVID-19, according to the BBC. Instead, researchers are now looking to T cells to gain a better understanding of how the body can potentially provide immunity to humans.
A number of studies have suggested that people infected with COVID-19 tend to have T cells that can target the virus. However, scientists are now also realizing that some people who can test negative for COVID-19 antibodies can test positive for T cells that identify the virus within the body. This has led some to believe that a certain level of immunity against the disease may be twice as common as previously assumed.
Thus far, the central role of T cells has been misunderstood by many looking into COVID-19, but it may explain why certain people are more susceptible to its symptoms than others.
As biopharmaceutical companies continue their search for a vaccine, the first Phase III clinical trial of a coronavirus vaccine in the U.S. began today, with Moderna and the National institute of Allergy and Infectious Diseases leading the way. The study is expected to enroll approximately 30,000 adult volunteers and will evaluate the safety and efficacy of the candidate. The ultimate goal is to determine whether it can prevent symptomatic COVID-19 after two doses. Volunteers will receive either two 100 microgram injections of the vaccine or a placebo 28 days apart.
Earlier this month, results from the Phase I trial of the vaccine were published in the New England Journal of Medicine and showed that it could induce an immune response in participants. It was shown to have mild side effects, including fatigue, chills, headache and muscle pain.
As the Moderna vaccine enters its Phase III trial, the race for a viable option is not slowing down, with companies such as Pfizer looking to make headway as well. On July 22, the U.S. Department of Health and Human Services and the Department of Defense announced an agreement with Pfizer to produce and deliver 100 million doses of a COVID-19 vaccine in the U.S. This is pending the vaccine’s successful manufacturing and regulatory approval.
Pfizer will deliver the doses in the U.S., assuming the product receives Emergency Use Authorization or licensure from the U.S. Food and Drug Administration (FDA), as outlined in FDA guidance. The presumed vaccine also must demonstrate its safety and efficacy in a large Phase 3 clinical trial.
If all goes according to plan, the approach will help the U.S. government achieve the goals established in its Operation Warp Speed program. Ideally, the government would like to begin delivering 300 million doses of safe and effective vaccine to the American people by the end of the year.
“Through Operation Warp Speed, we are assembling a portfolio of vaccines to increase the odds that the American people will have at least one safe, effective vaccine as soon as the end of this year,” said HHS Secretary Alex Azar, at the time of the announcement. “Depending on success in clinical trials, today’s agreement will enable the delivery of approximately 100 million doses of vaccine being developed by Pfizer and BioNTech.”