Children with natural immunity were better protected from COVID-19 infection and hospitalization than children who were vaccinated, according to a new study.
Children aged 5 to 11 with post-infection protection, or natural immunity from an infection with Omicron or a subvariant, and no vaccination had 88.4 percent protection against reinfection, researchers in North Carolina found. That was compared to 59.7 percent protection against Omicron from a primary series of a messenger RNA vaccine, or two doses of vaccine from Pfizer or Moderna, among the uninfected.
The protection remained higher over time until month eight when the protection from natural immunity among the unvaccinated was estimated to be 18.8 percent and the protection from vaccination was pegged at 22.5 percent.
Fifty percent effectiveness is considered the threshold for an effective vaccine, according to the U.S. Food and Drug Administration and the World Health Organization, but the effectiveness of the shots remained above that bar for just one month, the researchers found.
A monovalent booster, or a discontinued booster, elevated the protection for the vaccinated, including children with a previous infection, by just 24.4 percent after one month, dipping to 19.3 percent after five months. A bivalent booster, or one of the new shots cleared in the fall of 2022, boosted the protection by 76.7 percent after one month but the shielding fell to 47.3 percent on top of the original series after one more month.
Researchers did not provide separate estimates for the naturally immune and unvaccinated, and the vaccinated and infected, against hospitalization and death.
They pegged natural immunity for the 5 to 11 group against hospitalization and death at 87.5 percent after one month, compared with 73.3 percent from a primary series. After three months, natural immunity was estimated at 83.8 percent protection versus 39.3 percent from vaccination; after six months, natural immunity was pegged at 76.2 percent, compared to 2.9 percent for vaccination.
Even though the vaccines are authorized for the prevention of COVID-19, they have become increasingly worse at preventing infection. Authorities have shifted to promoting them as a tool to prevent severe disease, but that protection has also become subpar against Omicron and its subvariants, real-world data and studies show.
The waning effectiveness prompted not only the authorization of boosters with the same formulation as the primary series, but, later, the authorization without clinical data of new boosters aimed at the BA.4 and BA.5 subvariants of Omicron for all Americans aged 6 months and older.
The North Carolina researchers drew from The North Carolina COVID-19 Surveillance System, which contains testing data and COVID-related hospitalization and death information, as well as the COVID-19 Vaccine Management System, which holds vaccination records. The study focused on North Carolina residents 11 years of age and younger, from Oct. 29, 2021, to Jan. 6, 2023. They estimated the effectiveness of vaccination and natural immunity against infection, hospitalization, and death.
Researchers did not provide estimates of booster effectiveness against hospitalization and death. They said there was only one hospitalization and no deaths after receipt of a booster dose.
The study population was primarily unvaccinated because most children in the United States have not received a vaccine.
Data from children aged up to 4 years was also analyzed.
The protection from Omicron infection against reinfection among all children was estimated at 83.1 percent after one month. It was pegged at 55.7 percent one month after two doses of a vaccine among the uninfected. At five months, the former was 69.6 percent and the latter was 58.6 percent.
Natural immunity in the youngest age group after an Omicron infection was estimated at 63.3 percent against hospitalization and death one month later, remaining above 50 percent after 10 months.
Researchers included both the vaccinated and unvaccinated in the naturally immune group and did not provide a separate estimate of the protection the unvaccinated and naturally immune enjoyed.
Researchers did not provide an estimate of effectiveness for a primary series or boosters among the population against hospitalization and death.
The study was published as a preprint on Jan. 19.
Researchers said the study showed that “previous SARS-CoV-2 infection induced strong immunity against future infection, although the immunity waned gradually over time” and that “omicron infection induced strong immunity in both vaccinated and unvaccinated children.” SARS-CoV-2 causes COVID-19.
The researchers also said the results showed vaccination “was effective against omicron infection, hospitalization, and death, although the effectiveness waned over time” and that boosters “were effective.”
“Our study showed that the additional benefits of vaccination were similar between previously infected and previous uninfected children,” Dan-yu Lin, a professor in the University of North Carolina’s Department of Biostatistics, told The Epoch Times via email.
“Serious side effects are very rare. The benefits of vaccination outweighs the risk of side effects,” he added. The study did not evaluate vaccine safety or COVID-19 symptoms and Lin declined to provide evidence for the risk-benefit statement.
Limitations of the research include researchers wrongly believing that the Pfizer primary series for children aged 0 to 4 is only two doses. It’s actually three doses (pdf), because a two-dose regimen didn’t induce an adequate immune response, according to Pfizer. The third dose is a bivalent as of late 2022.