SARS-CoV-2 Transmission Risk to Household and Family Contacts by Vaccinated Healthcare Workers

Pratò, Simone; Paladino, María Emilia; Riva, Michele Augusto; Deni, Matteo; Belingheri, Michael

doi:10.1097/jom.0000000000002238

Cited by 8 publications

(7 citation statements)

References 9 publications

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“…However, no secondary infections were traced back to any of the breakthrough cases, which supports the inference that these workers were less contagious than unvaccinated persons, as has been reported previously. 4 , 5 , 17 , 18 Mandated isolation after positive results on RT-PCR assay regardless of vaccination status could have contributed to this observation. Most important, we found that low titers of neutralizing antibody and S-specific IgG antibody may serve as markers of breakthrough infection.…”

Section: Discussionmentioning

confidence: 91%

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

et al. 2021

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Background Despite the high efficacy of the BNT162b2 messenger RNA vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rare breakthrough infections have been reported, including infections among health care workers. Data are needed to characterize these infections and define correlates of breakthrough and infectivity. Methods At the largest medical center in Israel, we identified breakthrough infections by performing extensive evaluations of health care workers who were symptomatic (including mild symptoms) or had known infection exposure. These evaluations included epidemiologic investigations, repeat reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assays, antigen-detecting rapid diagnostic testing (Ag-RDT), serologic assays, and genomic sequencing. Correlates of breakthrough infection were assessed in a case–control analysis. We matched patients with breakthrough infection who had antibody titers obtained within a week before SARS-CoV-2 detection (peri-infection period) with four to five uninfected controls and used generalized estimating equations to predict the geometric mean titers among cases and controls and the ratio between the titers in the two groups. We also assessed the correlation between neutralizing antibody titers and N gene cycle threshold (Ct) values with respect to infectivity. Results Among 1497 fully vaccinated health care workers for whom RT-PCR data were available, 39 SARS-CoV-2 breakthrough infections were documented. Neutralizing antibody titers in case patients during the peri-infection period were lower than those in matched uninfected controls (case-to-control ratio, 0.361; 95% confidence interval, 0.165 to 0.787). Higher peri-infection neutralizing antibody titers were associated with lower infectivity (higher Ct values). Most breakthrough cases were mild or asymptomatic, although 19% had persistent symptoms (>6 weeks). The B.1.1.7 (alpha) variant was found in 85% of samples tested. A total of 74% of case patients had a high viral load (Ct value, <30) at some point during their infection; however, of these patients, only 17 (59%) had a positive result on concurrent Ag-RDT. No secondary infections were documented. Conclusions Among fully vaccinated health care workers, the occurrence of breakthrough infections with SARS-CoV-2 was correlated with neutralizing antibody titers during the peri-infection period. Most breakthrough infections were mild or asymptomatic, although persistent symptoms did occur.

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Section: Discussionmentioning

confidence: 91%

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

et al. 2021

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“…In terms of socio-demographics, younger HCWs had a slower rate of uptake. This is a concern as unvaccinated HCWs may pose a risk to vulnerable patients [23] , [24] , [25] , [26] . Building on this, HCWs of a Black or Mixed ethnic groups were less likely to receive a booster vaccination, compared with White HCWs.…”

Section: Discussionmentioning

confidence: 99%

COVID-19 booster vaccination uptake and infection breakthrough amongst health care workers in Wales: A national prospective cohort study

Bedston¹,

Lowthian²,

Jarvis³

et al. 2023

Vaccine

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“…Further studies on this topic are needed to modify policies on return to work of these subjects and to avoid social stigma and discrimination at the workplace. 16 , 17 …”

Section: Discussionmentioning

confidence: 99%

COVID-19 Vaccination and Asymptomatic Infection

Pratò

Paladino

Riva

et al. 2021

Journal of Occupational &Amp; Environmental Medicine

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Objective: To determine the incidence of COVID-19 and the duration of sick leave among asymptomatic healthcare workers (HCWs) after vaccination with BNT162b2. Methods: From October 2020 to March 2021, we determined the incidence of COVID-19 in a cohort of 671 asymptomatic HCWs before and after the vaccination. We also analyzed the days required to obtain a negative RT-PCR result after infection. Results: Prior to vaccination 105 (15.6%) HCWs were positive. Positive cases were reduced to 42 (7.5%) after the vaccination period ( P < 0.0001). A negative RT-PCR was observed at the first control in 80% of vaccinated HCWs and only in 37% before vaccination. Conclusions: Even in case of asymptomatic infection, vaccinated HCWs have a reduced incidence and a shorter period of sick leave than before vaccination, suggesting vaccination impacts on the sustainability of the health system and labor costs.

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SARS-CoV-2 Transmission Risk to Household and Family Contacts by Vaccinated Healthcare Workers

Cited by 8 publications

References 9 publications

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

COVID-19 booster vaccination uptake and infection breakthrough amongst health care workers in Wales: A national prospective cohort study

COVID-19 Vaccination and Asymptomatic Infection

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