key: cord-0870719-nkbbiitx authors: Kiefer, Miranda K.; Allen, Kenneth D.; Russo, Jessica R.; Ma'ayeh, Marwan; Gee, Stephen E.; Kniss, Doug; Cackovic, Michael; Costantine, Maged M.; Rood, Kara M. title: Decline in Sars‐CoV‐2 antibodies over 6‐month follow‐up in obstetrical healthcare workers date: 2021-08-22 journal: Am J Reprod Immunol DOI: 10.1111/aji.13490 sha: 8f8c3aae9b353f1da40fd795abe2076512d59922 doc_id: 870719 cord_uid: nkbbiitx PROBLEM: Limited data exists on the temporal trend of the Sars‐CoV‐2 immunologic response and duration of protection following natural infection. We sought to investigate the presence and duration of Sars‐CoV‐2 serum antibodies in obstetrical healthcare workers (HCW) on serial assessments over a 6‐month period, and to assess rates of vaccine acceptance and reported vaccine side effects among this cohort. METHOD OF STUDY: A prospective cohort study of a convenience sample of obstetrical HCWs at a tertiary hospital. Serum Sars‐CoV‐2 antibodies for Immunoglobulin G (IgG) and Immunoglobulin M (IgM) were measured longitudinally at four intervals: baseline, 4 weeks, 12 weeks, and 6 months. Participants completed voluntary surveys on COVID19 testing, high‐risk exposures, vaccine acceptance, and vaccine side effects. RESULTS: One hundred twenty‐six of 150 (84%) HCWs who volunteered for participation completed all four blood draws. Prevalence of seropositive HCWs based on positive Sars‐CoV‐2 IgG antibodies increased from 2% at baseline to 31% at 12 weeks but declined to 21% by 6 months. Forty‐two percent (19/43) of the participants considered seropositive for Sars‐CoV‐2 IgG antibodies at any of the initial three blood draws converted to seronegative status at the 6‐month follow‐up. Eighty‐seven percent (72/83) of participants who responded to a follow‐up survey were willing to accept the COVID19 vaccine. Rates of acceptance did not differ by participant antibody status. Those that experienced symptoms with the first injection were more likely to have positive Sars‐CoV‐2 IgG antibodies (36.8% vs. 9.6%, p = .01). CONCLUSION: Sars‐CoV‐2 IgG antibodies wane over time and may not provide prolonged and robust immune protection. This underscores the importance of vaccination and continued research in this area while the COVID19 pandemic continues. The rapid spread of the Sars-CoV-2 virus has led to the current COVID19 global pandemic. The social and economic consequences of this pandemic are vast, and until recently, the mainstay of mitigating this disease has been through health prevention measures such as social distancing, facial masking, and contact tracing. 1 With the rapid production, mass distribution, and robust vaccine acceptance of novel COVID19 vaccines, we now have an intervention that can end the pandemic. To date, 65% of the United States population has received at least a single dose of the Moderna, the Pfizer, or the Johnson and Johnson COVID19 vaccine; however, daily vaccination rates are decreasing. 2 This decline in vaccination is due to COVID19-associated vaccine hesitancy, from factors such as perceived rushed production, and limited safety and long-term data. 3 Still, others cite prior Covid19 infection and a perception of natural immunity, despite the lack of knowledge on the long-term protection such an infection may provide. Even though data suggest reduced re-infection rates in those that have had prior COVID19 infection, [4] [5] we do not know the duration of this protection, especially against variant strains. Furthermore, vaccination in those with prior infection is recommended and produces significantly higher antibody titer levels than those without prior infection. 6 Current data show high rates of COVID19 seroconversion by presence of Sars-CoV-2 Immunoglobulin G (IgG) antibodies following acute infection. 7, 8 However, recent data suggests a rapid decline in serum IgG antibody titers when followed serially for 60 days, [8] [9] [10] and a rate of reconversion to seronegative status ranging from 28% to 58% during this same study period. 9,10 Moreover, the half-life of Sars-CoV-2 IgG antibodies is suggested to be as short as 36-85 days. 11, 12 This is in stark contrast to antibodies to other known viral pathogens such as varicella, mumps, measles, and rubella all with calculated half-lives greater than 50 years. 13 Still, the data are mixed, and other studies cite rates of persistence of Sars-CoV-2 IgG antibodies ranging from 92-94% at 3-6 month follow ups. 12, 14 Information about the trend in Sars-CoV-2 IgG antibodies is of particular importance in obstetrical healthcare workers (HCW), as they are exposed to large volumes of asymptomatic patients with rapid turnover and have increased potential to spread COVID19 15 We sought to investigate the presence and duration of Sars-CoV-2 serum antibodies in obstetrical healthcare workers on serial assessments over a 6-month period. We additionally assessed rates of vaccine acceptance and reported vaccine side effects among this population. This was a prospective cohort study that investigated the longi- 150 female HCWs volunteered for participation. Median age of participants was 35 years old (IQR 29.5-47.5), 63% (n = 95) were registered nurses, and 75% (n = 113) were primarily employed in the inpatient setting. Forty-five percent (n = 68) of participants were tested for COVID19 by nasopharyngeal PCR antigen testing during the study period, of which 26% (n = 18/68) reported positive results (Table 1) . Three people did not complete any of the blood draws after volunteering, thus a total of 147 samples were available for analysis in the initial and 4-week follow-up blood draw. Six participants in the 12-week blood draw, and 15 participants in the 6-month blood draw were lost to follow up due to employment change or failure to present for collection. A total of 126 participants (84%) of those originally enrolled in the study had samples collected at all four time intervals (Figure 1 ). Sars-CoV-2 specific IgM antibodies were present in two participants (1.4%) and nine participants (6.1%) in the initial and 4-week follow up (Table 2) . Our results support previous reports demonstrating a rapid decline of serum Sars-CoV-2 specific IGG antibodies over time, and high rates of reconversion to seronegative status despite previous seropositivity. [8] [9] [10] This finding is concerning particularly due to the high incidence of vaccine hesitancy and decreasing daily vaccination rates in the United States, 2,3 and further supports the recommendation to vaccinate those with prior COVID19 infection. Interestingly, our cohort demonstrates a high rate of vaccine acceptance regardless of antibody status; however, those with positive antibodies were more likely to experience systemic side effects to the first vaccine injection. With the emergence of more deadly COVID19 variant strains, vaccination offers cross-protection, which may not be present with natural immunity. 17 Our study is limited by the fact that it is a convenience sample and thus made up entirely of female identifying participants. Demographic and Sars-CoV-2 testing, and exposure data were collected via voluntary surveys which is subject to bias. Additionally, our study demonstrates high rates of vaccine acceptance among HCW similar to others 21 ; however, those that responded to the follow-up survey may have been more inclined to respond if they already received the vaccine. In conclusion, Sars-CoV-2 specific IGG antibodies wane over time Research data are not shared. Miranda K. Kiefer https://orcid.org/0000-0002-7663-3774 Michael Cackovic https://orcid.org/0000-0002-0256-5799 Prevent Getting Sick Centers for Disease Control and Prevention. 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