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Southwest Center for Occupational and Environmental Health

Texas CARES recap: COVID-19 antibody project FAQs answered by Dr. George Delclos

HOUSTON (May 21, 2021) – George Delclos, MD, MPH, PhD, Professor in the Southwest Center for Occupational and Environmental Health within the Department of Epidemiology, Human Genetics and Environmental Sciences (EHGES) at the UTHealth School of Public Health spoke at the Texas CARES: Covid-19 antibody project webinar on Tuesday, May 18.

The Texas Coronavirus Antibody REsponse Survey, or Texas CARES, is a survey that will help us better understand the human antibody response to SARS-CoV-2, the virus that causes COVID-19. Survey participants will help us measure things like how many people in the survey have COVID-19 antibodies, and how long those antibodies last.

How does Texas CARES work?


Here are some highlights from the hour-long webinar, including answers to frequently asked questions (see below for webinar slides and full video):

  • If I have already received a COVID-19 vaccine, why do I need to know if I have antibodies? By participating in the survey, you will know if your body has built up antibodies either because of the vaccine or a prior infection, depending on the type of antibody test you get. By measuring them several times over a 6 to 9 month period, we can all learn about how persons in Texas have these antibodies and how long they last.
  • If I already was infected by COVID-19, why do I need the vaccine? Delclos: "Although it’s clear that having natural infection does prevent you from having additional COVID-19 infections, we don’t know how long that protection will last. We also know that, even if you’ve had a COVID-19 infection, you may be reinfected, although this is rare. In some cases, reinfection can be worse than the original infection. Finally, we also know that vaccination leads to higher levels of "neutralizing antibodies" against SARS-CoV-2 and its variants than natural infection.”
  • How effective are the COVID-19 vaccines? Delclos: “Both clinical trials and what we are seeing in the tens of millions vaccinated so far in the U.S. is that the three authorized vaccines (Pfizer, Moderna, and Johnson & Johnson) are very effective at preventing COVID-19 infection and, more importantly, nearly 100% effective at preventing severe illness or death from COVID-19. And the also appear to be quite effective at preventing transmission of COVID-19 to other persons.”
  • Why does the vaccine cause side effects? Delclos: “Most vaccine side effects are a result of the vaccines doing what they are supposed to do, that is, generating an immune response designed to protect us from getting sick with COVID-19. These side effects, which can be either local (in the arm) or more generalized (affecting the body) typically resolve in 24-48 hours"
  • How common is a severe reaction to a COVID-19 vaccine? Delclos: “The data says a severe allergic reaction (also known as anaphylaxis) has been descried mainly following administration of either of the two mRNA vaccines (Pfizer and Moderna). Although this is a serious side effect warranting immediate medical treatment, fortunately it is very rare, occurring in about 3 to 6 persons out of every million doses administered. Moreover, all vaccine administration sites are equipped with the necessary emergency treatment to administer it immediately.”
  • Are the vaccines effective against variants? Delclos: "Right now, the vaccines appear to be quite effective against the main variants circulating in the U.S., including the UK variant. The Indian variant (b.1.617) we need to keep an eye on. It has not penetrated the U.S. much, yet, so we don't know as much. It is also likely that new variants will emerge in the future, so we need to remain vigilant to make sure that either the current vaccines remain effective against them or that we are able to modify our vaccines to handle these possible variants."
  • Should I be concerned with blood clots if I am considering the Johnson & Johnson vaccine? Delclos: “In April, the CDC paused the Johnson & Johnson vaccine following reports of increased blood clots, officially known as TTS (Thrombosis and Thrombocytopenia Syndrome), that had occurred in about 6 women out of the nearly 7 million doses that had been administered at that point. The reason for the pause was to allow CDC and its advisors to review the data carefully. After about 7 or 10 days, CDC lifted the pause after determining that the benefits of the vaccine greatly outweighed the small risk of blood clots, although we all continue to monitor this situation. The risk is small, but real, but people forget that having COVID-19 also increases one’s risk of having blood clots, and that risk is much higher than the risk observed with the Johnson and Johnson vaccine.”
  • If a person was infected with COVID-19, how long should they wait to get the vaccine? Delclos: "In general, an actively infected person should wait at least 10 days before getting vaccinated. One exception to this, however, is if that person was treated for their COVID-19 infection with what’s known as a monoclonal antibody or if they received convalescent plasma. In those cases, CDC recommends waiting about 90 days before getting the vaccine.”