Patients who have recovered from COVID have shown to have antibodies that protect against a reinfection of the coronavirus up to 20 months after their infection, researchers found. Called "natural immunity," this is another type of immunity that some scientists are touting versus immunity from COVID vaccines.
According to The Epoch Times, researchers led by Dr. Dorry Segev, the director of the Epidemiology Research Group in Organ Transplantation at Johns Hopkins University found that 99% of study participants who tested positive for COVID still had antibodies against the COVID spike protein receptor-binding domain (RBD) up to 20 months following their infection.
In the Fall of 2021, Dr. Segev and his researchers called upon unvaccinated, healthy adults for the study and divided them into three groups. The first group was composed of 295 participants who tested positive for COVID in the past, while the second group had 275 participants who believed they had COVID and recovered but never got tested. The third group was composed of 246 people who did not think they ever had COVID and never tested positive.
Among the first group, only 2 of the 295 participants did not test positive for COVID antibodies. 293 tested positive for antibodies and there was no evidence that protection waned over time. In the second group, 55% of participants tested positive for COVID antibodies and the medial level among those who did was also lower. Finally, among the third group, 11% tested positive for COVID antibodies and had the lowest level among those who did test positive for the antibodies.
"The major takeaway is that natural immunity ... is strong and durable," Dr. Segev said. Dr. Nasia Safdar, a professor in the Division of Infectious Disease at the University of Wisconsin's School of Medicine and Public Health said that Dr. Segev's study showed promising results "but likely applicable only to a healthy adult population, with the ability and resources to go get a blood draw."
"We are probably missing the immunocompromised, older, frail group of people where immune response may be very different than other groups," Dr. Safdar suggested.
Dr. Jeffrey Klausner of the Keck School of Medicine of the University of Southern California remarked that Dr. Segev's study "confirms that those with prior infection will have detectable antibody and that antibody may persistent for up to 20 months." He believes it should help people be more confident about the natural immunity that they have against the virus.
The Hill reported that more than 65 million Americans have had COVID and have recovered from it, which meant that they too have natural immunity from the virus. Now, two years into the pandemic, the U.S. Centers for Disease Control and Prevention (CDC) is finally acknowledging that natural immunity provides strong protection against COVID.
A new CDC report that analyzed COVID cases in California and New York between May 30 to November 20, 2021 analyzed the risk for COVID reinfection among four groups of people, unvaccinated people wihout a prior COVID infection, vaccinated without a prior COVID infection, vaccinated people with a prior COVID infection, and unvaccinated people with a prior COVID infection.
Results showed that during this period before the Delta variant spread, the incidence of COVID among those with immunity from both vaccination and a previous infection was "32.5-fold lower in California and 19.8-fold lower in New York," versus those who only had been vaccinated but did not have a prior infection, which showed "6.2-fold lower [incidence] in California and 4.5-fold lower [incidence] in New York." Meanwhile, those with natural immunity had "29.0-fold lower [incidence] in California and 14.7-fold lower [incidence] in New York." Researchers noted that hospitalization rates showed similar results.
