How long after your second shot can you consider yourself protected?
While the wintry weather shut down many of Texas’ COVID vaccination efforts, it didn’t stem the flow of questions about vaccine safety and efficacy.
The Houston Chronicle’s COVID-19 Help Desk is here to answer your questions. Every week, a Chronicle reporter answers readers’ questions about how the virus works and what to expect with the vaccine.
How long do people who have COVID-19 have to wait to get the vaccine?
The decision to delay vaccine shots for people who have active COVID-19 infections is rooted in public health concerns.
Vaccine site staff want to minimize their risk of catching the virus, which is why they would ask patients — especially if they’re symptomatic — to reschedule.
There’s no data to support a minimum wait time yet, said Namandje Bumpus, director of the pharmacology and molecular sciences department at Johns Hopkins University in Baltimore. However, public health entities such as the Centers for Disease Control and Prevention recommend waiting 90 days, especially if a patient has been treated with convalescent plasma or antibody infusions, because lingering antibodies may provide temporary immunity.
“With there being a
lower supply of vaccine, people can decide to talk to their health care provider and potentially wait up to a few months before getting vaccinated,” said Bumpus, who runs a drug development lab that researches treatments and prevention of infectious diseases.
People should wait until their symptoms have cleared or they meet the criteria to leave quarantine before vaccination, according to the CDC.
If I’ve had Guillain-Barre Syndrome with a flu or tetanus shot, what is my risk with the COVID-19 vaccine?
Guillain-Barre Syndrome is a rare, neurological inflammation that attacks the nervous system, causing pain, weakness, and more rarely, paralysis and permanent injury. While researchers don’t understand exactly what causes it, the syndrome is linked to some types of vaccines. About 3,000 people are diagnosed with Guillain-Barre Syndrome every year in the U.S.
Last fall, U.K. scientists studied the links between the disorder and COVID-19 and found no increases in Guillain-Barre Syndrome due to the virus. No cases of the syndrome have been reported in the vaccine trials so far, either, according to the CDC.
However, if you’ve previously had allergic reactions to polyethylene glycol or polysorbate, you should consult your doctor before receiving a COVID-19 vaccine. Ultimately, medical experts say the risk of Guillain-Barre Syndrome is extremely low.
“Prior history of Guillain-Barre Syndrome is not a contraindication or precaution to vaccination in general,” Bumpus said.
How long after your second shot can you consider yourself protected?
As of Wednesday, 1.2 million Texans have received both shots of the Pfizer-BioNTech or Moderna vaccines, 199,000 of whom reside in Harris County. But even if your first injection was in January, you may not have full immunity until the end of February or early March.
Pfizer and Moderna had different criteria for measuring efficacy in their clinical trials. Pfizer, for instance, started testing vaccine recipients for COVID-19 symptoms seven days after the second dose, while Moderna waited until the 14-day mark.
You likely won’t reach full protection for one to two weeks after the second dose, Bumpus said. The body still needs time to develop an antibody reaction to the vaccine.
Scientists also still don’t know whether the vaccine protects people from transmitting the virus to someone else. Vaccine manufacturers are studying that in ongoing vaccine trials.
“Folks definitely would need to continue to follow non-vaccine measures for protecting themselves, such as the face mask, social distancing and hand washing,” Bumpus said.
I’m immunocompromised and worried I won’t mount a full response to the virus. Will I be protected with the vaccine?
Immunocompromised people are allowed to receive the COVID vaccine, but patients need to consult with their doctors on whether their medical conditions could be a factor in using a certain vaccine.
The available data from Pfizer and Moderna trials does not include information on how it affects people who are HIV-positive or other immunocompro-mising conditions, or whether the efficacy rate changes.
“There is potential for reduced immune response,” Bumpus said. “Right now, we don’t have a way of measuring or predicting what that would be and how it would impact effectiveness.”