GAO: A Herd Immunity For COVID-19 Primer
#16,809
Despite being heavily touted by politicians as being the `way out of the pandemic', achieving herd immunity against COVID-19 has always been a long shot (see GAO: A Herd Immunity For COVID-19 Primer).
In April of 2020 (see COVID-19: From Here To Immunity) and again in July of that year (see COVID-19: From here To Immunity (Take Two) we looked at some of the obstacles that might either delay or prevent society from achieving herd immunity - either from natural infection or a vaccine - to the novel coronavirus.
The other assumption - that COVID didn't mutate as rapidly as influenza - has also been proven overly optimistic, and we've seen the steady procession of new, increasingly more transmissible, variants over the past 16 months (Alpha, Delta, Omicron, BA.2, BA.2.12.1, BA.4 and BA.5).
Still, many people cling to the idea that once they've had COVID, they are protected. Some even believe `natural infection' provides more, and longer-lasting, protection than the vaccine.
While both can, and do, provide some degree of protection, it is far from permanent, and far less effective against the newer Omicron variants.
We've a new study out of Boston Children's Hospital, Harvard Medical School, and the FDA that finds that kids infected with COVID before 2022 (and the emergence of Omicron) have very little protection against Omicron variants in 2022.
However, children who were double-vaccinated, showed higher titers against Alpha, Beta, Gamma, Delta and Omicron
First the link and abstract, then links and excerpts from two press releases.
Cross-reactive immunity against the SARS-CoV-2 Omicron variant is low in pediatric patients with prior COVID-19 or MIS-C
Nature Communications volume 13, Article number: 2979 (2022) Cite this article
Abstract
Neutralization capacity of antibodies against Omicron after a prior SARS-CoV-2 infection in children and adolescents is not well studied. Therefore, we evaluated virus-neutralizing capacity against SARS-CoV-2 Alpha, Beta, Gamma, Delta and Omicron variants by age-stratified analyses (<5, 5–11, 12–21 years) in 177 pediatric patients hospitalized with severe acute COVID-19, acute MIS-C, and in convalescent samples of outpatients with mild COVID-19 during 2020 and early 2021.
Across all patients, less than 10% show neutralizing antibody titers against Omicron. Children <5 years of age hospitalized with severe acute COVID-19 have lower neutralizing antibodies to SARS-CoV-2 variants compared with patients >5 years of age. As expected, convalescent pediatric COVID-19 and MIS-C cohorts demonstrate higher neutralization titers than hospitalized acute COVID-19 patients.
Overall, children and adolescents show some loss of cross-neutralization against all variants, with the most pronounced loss against Omicron. In contrast to SARS-CoV-2 infection, children vaccinated twice demonstrated higher titers against Alpha, Beta, Gamma, Delta and Omicron. These findings can influence transmission, re-infection and the clinical disease outcome from emerging SARS-CoV-2 variants and supports the need for vaccination in children.
You'll find two summaries provided (first) by Boston Children's Hospital.
Previous COVID-19 or MIS-C does not protect kids from Omicron
Posted on June 3, 2022 by Nancy Fliesler | Clinical, Research
(Excerpt)
The researchers studied blood samples from children and adolescents who had COVID-19 or multisystem inflammatory syndrome in children (MIS-C) during 2020 and early 2021, before Omicron emerged. Of these, 62 had been hospitalized with severe COVID-19 and 65 with MIS-C; another 50 children had recovered from mild COVID-19 and hadn’t been hospitalized.
In the laboratory, the team exposed the children’s blood samples to a pseudovirus, which is derived from the SARS-CoV-2 coronavirus, but stripped of its virulence. They then measured how well antibodies in the samples were able to neutralize five different variants of concern: Alpha, Beta, Gamma, Delta, and Omicron.
Overall, children and adolescents showed some loss of antibody neutralization against later-emerging variants. But the loss was most pronounced for Omicron: fewer than 10 percent had sufficient neutralizing antibodies to fight it off.
(Continue . . . )
And secondly by Harvard Medical School.
Infected, UnprotectedStudy finds previous COVID-19 infection doesn’t protect children from omicron
By NANCY FLIESLER | Boston Children's June 6, 2022 Research
Fewer than 10 percent of children who contracted COVID-19 in 2020 or early 2021 developed antibodies that can fight off the omicron variant of SARS-CoV-2, according to a new study led by researchers at Harvard Medical School, Boston Children’s Hospital, and the U.S. Food and Drug Administration.
The findings, published May 27 in Nature Communications, echo studies of adults showing that contracting COVID-19 once doesn’t guarantee antibody protection from repeat infection.
With BA.4 and BA.5 on the ascendant in the United States, and more variants likely to follow, relying on year-old acquired immunity is a dangerous game.
Vaccines may not fully prevent infection with these new variants, but they have been proven to reduce severity of illness, rates of hospitalization, and deaths.
