Antibodies fighting original SARS-CoV-2 virus weaker against omicron
Photo by AdobeStock_473045661 photo credit
Fast Facts Infection-induced
SARS-CoV-2 seroprevalence
In December 2021, the B.1.1.529 (Omicron) variant of SARS-CoV-2, the virus that causes COVID-19, became predominant in the United States. Traditional methods of disease surveillance do not capture all COVID-19 cases because some are asymptomatic, not diagnosed, or not reported; therefore, the proportion of the population with SARS-CoV-2 antibodies (i.e., seroprevalence) can improve understanding of population- level incidence of COVID-19.
75%
of children and adolescents had serologic evidence of previous infection with SARS-CoV-2 as of
February 2022, with approximately one third becoming newly sero- positive since December 2021.
24.2% was the overall U.S. serop-
revalence increase from 33.5% in December 2021 to 57.7% in Febru- ary 2022, for all age groups
31%
of children aged 0–11 years had increased seroprevalence in the same December 2021 to February 2022 time period
73,869
was the median sample size per 4-week period that the CDC sampled between Sep- tember 2021–January 2022
28.6%
Was the greatest seroprevalence increase among persons aged 12–17 years, from 45.6% to 74.2%
27.2%
Was second highest serop- revalence increase among adults aged 18–49 years when it went from 36.5% to 63.7%
Source: CDC
https://www.cdc.gov/mmwr/volumes/71/ wr/
mm7117e3.htm?
6 JUNE 2022
MLO-ONLINE.COM
A recent study from Johns Hopkins Medicine and the National Institute of Allergy and Infectious Diseases sug- gests vaccine-derived antibodies that prevent binding by the original strain of the virus, SARS-CoV-2, do not work as well with the omicron strain, leaving even vaccinated and boosted people open to breakthrough COVID-19, ac- cording to a news release. Research findings were posted on-
line, in the Journal of Clinical Investiga- tion Insights. “Previous research has shown
vaccine-induced antibodies respond to the original strain of SARS-CoV-2 by inhibiting the virus’s ability to bind to angiotensin-converting enzyme 2 [commonly known as ACE2], the receptor on a cell’s surface through which SARS-CoV-2 gains entry,” says study senior author Joel Blankson, MD, PhD, Professor of Medicine at the Johns Hopkins University School of Medicine. “Our study suggests those same anti- bodies yield less ACE2 inhibition with the omicron strain, opening the door to a breakthrough COVID-19 infection.” To conduct their study, Blankson and his colleagues analyzed both the humoral (SARS-CoV-2 specific antibod- ies circulating in the bloodstream and produced by B lymphocytes, or B cells) and cellular (direct attack on the virus by T lymphocytes, or T cells) immune responses in 18 healthy and fully vac- cinated people, ages 23 to 62 (mean age of 30), who experienced breakthrough infections within 14 to 92 days (median of 50 days) after receiving a booster CO- VID-19 vaccine. Fourteen participants received a booster of the Pfizer-BioN- Tech messenger RNA (mRNA) vaccine, one was boosted with the Moderna mRNA vaccine, and the remaining three had an mRNA booster following their initial dose of the Johnson & Johnson viral vector vaccine. The humoral and cellular immune responses of those participants with breakthrough infections were com- pared with those from a control group of 31 participants, ages 21 to 60, who received similar COVID-19 vaccina- tions and boosters, and had no prior infection with SARS-CoV-2. Although the researchers were not able to document that the breakthrough infections were from the omicron strain, they say it’s a strong probability because the omicron variant accounted for more than 90% of the COVID-19 cases treated at The Johns Hopkins Hospital (where
the study was conducted) during the time when the study participants be- came symptomatic. “When we tested antibody-mediated inhibition of SARS-CoV-2 spike protein binding to ACE2, we found that serum from study participants with break- through COVID-19 — most likely the result of omicron infection — had an- tibodies that strongly stopped binding by the original strain virus as expected but didn’t carry out that function as well when responding to the omicron strain,” says Blankson. The levels of antibodies that inhibited
spike protein binding to ACE2 — high for original strain virus but reduced for omicron — were similar for both the participants with breakthrough infec- tions and those in the control group. The specific reduction in ACE2-inhib- iting antibodies responding to omicron, Blankson says, differs from what was seen in previously studied breakthrough infections with the alpha variant. In those cases, infected individuals were found to have lower overall antibody levels to the original virus strain. This was shown in a second recent
study, also co-authored by Blankson, looking at the blood plasma of 15 mRNA vaccine recipients. “The comparable strong T cell re- sponses for the original and omicron strains in both studies could explain why people, like our study participants, who have breakthrough COVID-19 cases typically experience only mild symptoms during the course of their illness,” he explained.
Mothers with postpartum depres- sion benefit from screening
Cedars-Sinai researchers identified comprehensive nurse training as key to successful hospital screening for mood disorders after childbirth. Nurse educa- tion is the key to successfully screening women for postpartum depression, which affects some 15% of mothers, according to a new quality improve- ment (QI) study from Cedars-Sinai. “Training that helped nurses get com- fortable with the topic of depression and to develop a non-judgmental attitude and openness to a patient’s questions and concerns is critical,” said Eynav Ac- cortt, PhD, principal investigator of the QI review and Director of the Reproductive Psychology Program at Cedars-Sinai. Depression and anxiety during
pregnancy or in the first 12 months after delivery is one of the most com- mon perinatal medical complications. Postpartum depression that sets in after childbirth is often characterized by per-
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