36% Of Those Who Had Covid-19 Didn’t Develop Antibodies, Study Says (link)
A study just published in the journal Emerging Infectious Disease found that 36% of those who had had Covid-19 didn’t have antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in their blood.
The Study
We studied 72 persons, all of whom had a previous positive RT-PCR test but were symptom-free for >3 weeks before blood was collected for testing (Table). Only 2 persons (3%) reported no symptoms, whereas 13 (18%) persons reported mild disease, 48 (67%) reported moderate disease, and 9 (12%) reported severe disease (Appendix Table 1).
We tested plasma samples (n = 144) collected at enrollment and follow-up visits for antibodies to the spike protein by using a validated ELISA (Appendix). Only 46 of the 72 participants had detectable IgG responses, IgA responses, or both (Table); reciprocal endpoint titers ranged from 182 to >312,500 (Appendix Table 2). Analysis of the same samples for receptor-binding domain (RBD) and nucleocapsid (N) antibodies yielded very similar results (Appendix Figure 1). All persons with spike protein antibodies also had detectable RBD (IgG, IgM, or both) or N (IgG) protein responses, except for 1 participant whose spike protein endpoint titers were very low (Appendix Table 2). In contrast, 26 participants remained seronegative, despite the testing of up to 3 samples per person for IgA, IgM, and IgG against multiple antigens as well as neutralizing antibodies. Thus, 36% of our cohort represented serologic nonresponders.
From "Predictors of Nonseroconversion after SARS-CoV-2 Infection" at:
https://wwwnc.cdc.gov/eid/article/27/9/21-1042-f1
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In response to this post by NJHoo)
Link: 36% Of Those Who Had Covid-19 Didn’t Develop Antibodies, Study Says
Posted: 01/07/2022 at 12:34PM