Lauren Dempsey, MS in Biomedicine and Law, RN, FISM News
On Wednesday the CDC released a new study that analyzed data on case rates and hospitalizations between May 2021 and November 2021.
The results of this study are consistent with what many health experts have been saying all along: natural immunity provides adequate, if not superior protection against reinfection, severe illness, and hospitalization in the event that reinfection does occur. This is promising for the millions of Americans who have contracted the virus but continue to be disparaged for declining to vaccinate against an illness that they’ve already had.
The CDC researchers compiled data from New York State and California in an effort to determine the impact of vaccination during the Delta surge of the pandemic. There were over 130,000 deaths through November 30, 2021 in the two states, thought the study authors fail to mention the vaccination status of the deceased.
The study examined records from lab tests, hospitalization surveillance, and an immunization registry and separated the individuals into four groups characterized by vaccination status and a previous laboratory-confirmed diagnosis of COVID-19.
The four cohorts included “persons who were 1) unvaccinated with no previous laboratory-confirmed COVID-19 diagnosis, 2) vaccinated (14 days after completion of a primary COVID-19 vaccination series) with no previous COVID-19 diagnosis, 3) unvaccinated with a previous COVID-19 diagnosis, and 4) vaccinated with a previous COVID-19 diagnosis.”
The study results indicated that while vaccination provides protection, so does natural immunity, which in a previous study the CDC had denied the benefits of surviving previous infection. The positive case rates were lowest among groups who had previous infection or received the vaccines and found that natural immunity was greatest after the Delta variant had become the predominant strain. This coincided with the decline of vaccine-induced immunity provided by vaccination.
Interestingly, when the Delta variant became the primary circulating variant in the United States, the data indicated that rates of infection “increased more rapidly among the vaccinated group with no previous COVID-19 diagnosis than among both the vaccinated and unvaccinated groups with a previous COVID-19 diagnosis.” This could be attributed to the poor efficacy of the vaccines over time, which diminished within 4 to 6 months post-vaccination.
The study authors were able to identify that infection rates in vaccinated individuals without a previous COVID-19 infection varied by the vaccine they received. There were more infections among individuals who received the Johnson & Johnson vaccine, followed by Pfizer-BioNTech, and then Moderna.
The authors admit that the information analyzed in this study did not account for the approval of boosters and the temporary immunity that is provided or the wave of the Omicron variant. The agency continues to urge the American people that the safest and most effective way to prevent COVID-19 infection is through “vaccination, additional doses, and booster doses are recommended for all eligible persons.” Health officials continue to encourage vaccination, regardless of previous infection.
However, the data seems to suggest that natural immunity contributes to herd immunity as well as offers adequate protection against COVID-19. With this newly available data and admission from the CDC one is left to wonder if government officials and public health experts will change their stance on dismissing natural immunity when discussing vaccination.