The protective effect of SARS-CoV-2 antibodies in Scottish healthcare workers

Seroprevalence of SARS-CoV-2 antibodies among oral health care workers with natural seroconversion: a systematic review and meta-analysis

Aerosol and droplet exposure makes oral health care workers (OHCWs) highly susceptible to transmissible infections, for example with SARS-CoV-2. Population-based screening is useful in understanding public health interventions in COVID-19. This systematic review with meta-analysis presents the prevalence of SARS-CoV-2 antibodies among OHCWs. An electronic search has been performed to identify records indexed in Medline, Web of Science, Scopus, and the Cochrane Library until December 2023. All observational studies providing data on SARS-CoV-2 antibodies in OHCWs with natural seroconversion were included. The quality of 722 records was evaluated using the Joana Brigg's Institute (JBI) critical appraisal tool. Finally, ten studies were considered as eligible encompassing point-seroprevalence data on 6,083 dental professionals (dentists, assistants, and administrative staff) from seven European countries and Brazil. The antibody seroprevalence was pooled by a meta-analysis performed with MedCalc® statistical software. Applying random effects model, the overall seroprevalence of immunoglobulin G antibodies among OHCWs was estimated at 13.49% (95% CI 9.15-18.52%). The data indicate a somewhat increased occupation-specific risk for COVID-19 but more studies are required, especially later in the pandemic and following vaccination.

The Dynamics of Antibody Titres Against SARS-CoV-2 in Vaccinated Healthcare Workers: A Systemic Literature Review

Background and Objectives: Given that COVID-19 vaccination is a relatively recent development, particularly when compared to immunisation against other diseases, it is crucial to assess its efficacy in vaccinated populations. This literature review analysed studies that monitored antibody titres against SARS-CoV-2 in healthcare workers who received COVID-19 vaccines. Methods: Using the PICO (Population, Intervention, Comparators, Outcomes) model recommended in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines we included 43 publications which analyse antibody dynamics following primary vaccination, the effects of booster doses, and the influence of factors such as COVID-19C infection, age, and sex on antibody kinetics. Results: All the studies demonstrated a strong immunogenic response to the vaccines. Re-gardless of the vaccine used, over 95% of the pre-vaccination seronegative population be-came seropositive in all studies. Depending on the sampling intervals provided by the re-searchers, antibody levels were quantitatively highest during the first three months after vaccination, but levels inevitably declined over time. The monthly decline in antibodies observed in all these studies highlighted the necessity for booster doses. Studies analysing the impact of revaccination on antibody dynamics have confirmed that revaccination is an effective tool to boost humoral immunity against SARS-CoV-2. An-tibodies appear to persist for a longer period of time after revaccination, although they are subject to similar factors influencing antibody dynamics, such as age, comorbidities, and exposure to COVID-19. In addition, heterogeneous revaccination strategies have been shown to be more effective than homogeneous revaccination. Conclusions: Our review demonstrated that antibody levels against SARS-CoV-2 inevitably decline after vaccination, leaving the question of ongoing booster strategies open. The studies reviewed provided evidence of the effectiveness of booster vaccination, despite differences in age, sex, and prior COVID-19 infection. This suggests that repeated vaccination remains a highly effective method for mitigating the continued threat posed by COVID-19.

Protective effectiveness of previous infection against subsequent SARS-Cov-2 infection: systematic review and meta-analysis

Background

The protective effectiveness provided by naturally acquired immunity against SARS-CoV-2 reinfection remain controversial.

Objective

To systematically evaluate the protective effect of natural immunity against subsequent SARS-CoV-2 infection with different variants.

Methods

We searched for related studies published in seven databases before March 5, 2023. Eligible studies included in the analysis reported the risk of subsequent infection for groups with or without a prior SARS-CoV-2 infection. The primary outcome was the overall pooled incidence rate ratio (IRR) of SARS-CoV-2 reinfection/infection between the two groups. We also focused on the protective effectiveness of natural immunity against reinfection/infection with different SARS-CoV-2 variants. We used a random-effects model to pool the data, and obtained the bias-adjusted results using the trim-and-fill method. Meta-regression and subgroup analyses were conducted to explore the sources of heterogeneity. Sensitivity analysis was performed by excluding included studies one by one to evaluate the stability of the results.

Results

We identified 40 eligible articles including more than 20 million individuals without the history of SARS-CoV-2 vaccination. The bias-adjusted efficacy of naturally acquired antibodies against reinfection was estimated at 65% (pooled IRR = 0.35, 95% CI = 0.26-0.47), with higher efficacy against symptomatic COVID-19 cases (pooled IRR = 0.15, 95% CI = 0.08-0.26) than asymptomatic infection (pooled IRR = 0.40, 95% CI = 0.29-0.54). Meta-regression revealed that SARS-CoV-2 variant was a statistically significant effect modifier, which explaining 46.40% of the variation in IRRs. For different SARS-CoV-2 variant, the pooled IRRs for the Alpha (pooled IRR = 0.11, 95% CI = 0.06-0.19), Delta (pooled IRR = 0.19, 95% CI = 0.15-0.24) and Omicron (pooled IRR = 0.61, 95% CI = 0.42-0.87) variant were higher and higher. In other subgroup analyses, the pooled IRRs of SARS-CoV-2 infection were statistically various in different countries, publication year and the inclusion end time of population, with a significant difference (p = 0.02, p < 0.010 and p < 0.010), respectively. The risk of subsequent infection in the seropositive population appeared to increase slowly over time. Despite the heterogeneity in included studies, sensitivity analyses showed stable results.

Conclusion

Previous SARS-CoV-2 infection provides protection against pre-omicron reinfection, but less against omicron. Ongoing viral mutation requires attention and prevention strategies, such as vaccine catch-up, in conjunction with multiple factors.

COVID-19 case management in primary dental care settings in Yorkshire and the Humber

Introduction Emerging guidance during the COVID-19 pandemic aimed to minimise transmission risk within dental settings. This service evaluation provides an overview of reported cases of COVID-19 among primary dental care staff within Yorkshire and the Humber.Methods Data for COVID-19 cases reported within dental practices between November 2020 and August 2021 were extracted from the Public Health England, Health Protection Zone database and summarised using descriptive statistics.Results In total, 421 cases across 223 dental practices were reported, with 221 close contacts and 77 outbreaks identified. Cases/contacts were highest among dental nurses (51/49%). Household and community (42/22%) were the most frequently reported sources of transmission, with the majority of staff-to-staff contacts (60%) occurring in communal/non-clinical areas.Discussion There was a low number of reported COVID-19 cases/contacts among dental professionals, with most cases suspected to have acquired the infection from outside of the dental setting. The majority of personal protective equipment breaches occurred within communal/non-clinical areas. When infection prevention and control guidance was followed, there were no incidences of staff or patients becoming contacts or cases.Conclusion With adherence to strict protocols, the risk of COVID-19 transmission in the dental setting was low within the context of this review. The evaluation highlighted the importance of collaborative working during the pandemic.

Risk of SARS-CoV-2 infection in dental healthcare workers - a systematic review and meta-analysis

Background

Mounting evidence supports an association between the use of personal protective equipment (PPE) and the risk of infection from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in dental healthcare workers (DCW). However, the prevalence and incidence of SARS-CoV-2 infections in the setting of dental care remains poorly characterized.

Methods

A systematic review and meta-analysis of studies published prior to Mai 2023 providing epidemiological data for the occurrence of SARS-CoV-2 in DCW was performed. A random-effects model was used to calculate pooled estimates and odds ratios (ORs) with corresponding 95% confidence intervals (CIs). The associated factors were narratively evaluated. Risk of bias was assessed using the Joanna Briggs Institute tool for prevalence studies.

Results

Twenty-nine eligible studies were identified including a total of 85,274 DCW at risk; 27 studies met the criteria for the meta-analysis. Among the included DCW, the overall prevalence of SARS-CoV-2 was 11.8% (13,155/85,274; 95%CI, 7.5%-17%), whereby the degree of heterogeneity between the studies was considerable (I2=99.7%). The pooled prevalence rate for dentists and dental hygienists alone was 12.7% (1943/20,860; 95%CI, 8.0%-18.0%), showing significantly increased odds of contracting a SARS-CoV-2 infection compared to dental assistant personnel, the prevalence rate for which was less than half, at 5.2% (613/15,066; OR=2.42; 95% CI, 2.2-2.7). In the subgroup of 17 studies from countries with high income there was a significantly lower prevalence rate of 7.3% (95% CI, 5%-10%) in DCW compared to the prevalence rate in low- and middle-income countries, which came to 20.8% (95% CI, 14%-29%; p<0.001). In 19 out of the 29 studies (65.5%), specific information on the use of and adherence to PPE was absent while in the reports with concrete figures the wearing of N95 (or at least surgical masks) by DCW appeared to be associated with lower SARS-CoV-2 prevalence rates.

Conclusions

DCW were, depending in each case on their proximity to patients, at particular risk of SARS-CoV-2 infection during the COVID-19 pandemic. Until a significant level of vaccination protection against newer SARS-CoV-2 variants can be built up in the population, dental healthcare facilities should further maintain their focus on using PPE according to current guidelines.

The Scottish COVID Cancer Immunity Prevalence Study: A Longitudinal Study of SARS-CoV-2 Immune Response in Patients Receiving Anti-Cancer Treatment

BACKGROUND

Cancer and anti-cancer treatment (ACT) may be risk factors for severe SARS-CoV-2 infection and limited vaccine efficacy. Long-term longitudinal studies are needed to evaluate these risks. The Scottish COVID cancer immunity prevalence (SCCAMP) study characterizes the incidence and outcomes of SARS-CoV-2 infection and vaccination in patients with solid tumors undergoing ACT. This preliminary analysis includes 766 patients recruited since May 2020.

METHODS

Patients with solid-organ cancers attending secondary care for active ACT consented to the collection of routine electronic health record data and serial blood samples over 12 months. Blood samples were tested for total SARS-CoV-2 antibody.

RESULTS

A total of 766 participants were recruited between May 28, 2020 and October 31, 2021. Most received cytotoxic chemotherapy (79%). Among the participants, 48 (6.3%) were tested positive for SARS-CoV-2 by PCR. Infection rates were unaffected by ACT, largely aligning with the local population. Mortality proportion was not higher with a recent positive SARS-CoV-2 PCR (10.4% vs 10.6%). Multivariate analysis revealed lower infection rates in vaccinated patients regardless of chemotherapy (HR 0.307 [95% CI, 0.144-0.6548]) or immunotherapy (HR 0.314 [95% CI, 0.041-2.367]) treatment. A total of 96.3% of patients successfully raised SARS-CoV-2 antibodies after >2 vaccines. This was independent of the treatment type.

CONCLUSION

This is the largest on-going longitudinal real-world dataset of patients undergoing ACT during the early stages of the COVID-19 pandemic. This preliminary analysis demonstrates that patients with solid tumors undergoing ACT have high protection from SARS-CoV-2 infection following COVID-19 vaccination. The SCCAMP study will evaluate long-term COVID-19 antibody trends, focusing on specific ACTs and patient subgroups.

Designing an optimal sequence of non-pharmaceutical interventions for controlling COVID-19

The COVID-19 pandemic has had an unprecedented impact on global health and the economy since its inception in December, 2019 in Wuhan, China. Non-pharmaceutical interventions (NPI) like lockdowns and curfews have been deployed by affected countries for controlling the spread of infections. In this paper, we develop a Mixed Integer Non-Linear Programming (MINLP) epidemic model for computing the optimal sequence of NPIs over a planning horizon, considering shortages in doctors and hospital beds, under three different lockdown scenarios. We analyse two strategies - centralised (homogeneous decisions at the national level) and decentralised (decisions differentiated across regions), for two objectives separately - minimization of infections and deaths, using actual pandemic data of France. We linearize the quadratic constraints and objective functions in the MINLP model and convert it to a Mixed Integer Linear Programming (MILP) model. A major result that we show analytically is that under the epidemic model used, the optimal sequence of NPIs always follows a decreasing severity pattern. Using this property, we further simplify the MILP model into an Integer Linear Programming (ILP) model, reducing computational time up to 99%. Our numerical results show that a decentralised strategy is more effective in controlling infections for a given severity budget, yielding up to 20% lesser infections, 15% lesser deaths and 60% lesser shortages in healthcare resources. These results hold without considering logistics aspects and for a given level of compliance of the population.

Likelihood of COVID-19 reinfection in an urban community cohort in Massachusetts

Background

Understanding the association of prior SARS-CoV-2 infection with subsequent reinfection has public health relevance.

Objective

To explore COVID-19 severity and SARS-CoV-2 infection and reinfection rates.

Design

Retrospective cohort study.

Setting

Boston, Massachusetts, during the first COVID-19 surge (01/01/2020-05/31/2020; Period-1) and after the first surge (06/01/2020-02/28/2021; Period-2); Period-2 included the second surge (11/01/2020-02/28/2021).

Participants

Patients in an academic medical center and six community health centers who received a clinical diagnosis of COVID-19 between 01/01/2020 and 05/31/2020 or SARS-CoV-2 testing between 01/01/2020 and 02/28/2021.

Measurements

COVID-19 severity was compared between Period-1 and Period-2. Poisson regression models adjusted for demographic variables, medical comorbidities, and census tract were used to assess reinfection risk among patients with COVID-19 diagnoses or SARS-CoV-2 testing during Period-1 and additional SARS-CoV-2 testing during Period-2.

Results

Among 142,047 individuals receiving SARS-CoV-2 testing or clinical diagnoses during the study period, 15.8% were infected. Among COVID-19 patients, 22.5% visited the emergency department, 13% were hospitalized, and 4% received critical care. Healthcare utilization was higher during Period-1 than Period-2 (22.9% vs. 18.9% emergency department use, 14.7% vs. 9.9% hospitalization, 5.5% vs. 2.5% critical care; p < 0.001). Reinfection was assessed among 8961 patients with a SARS-CoV-2 test or COVID-19 diagnosis in Period-1 who underwent additional testing in Period-2. A total of 2.7% (n = 65/2431) with SARS-CoV-2 in Period-1 tested positive in Period-2, compared with 12.6% (n = 821/6530) of those who initially tested negative (IRR of reinfection = 0.19, 95% CI: 0.15-0.25).

Conclusions

Prior SARS-CoV-2 infection among this observational cohort was associated with an 81% lower reinfection rate.

The Protection of Naturally Acquired Antibodies Against Subsequent SARS-CoV-2 Infection: A Systematic Review and Meta-Analysis

The specific antibodies induced by SARS-CoV-2 infection may provide protection against a subsequent infection. However, the efficacy and duration of protection provided by naturally acquired immunity against subsequent SARS-CoV-2 infection remain controversial. We systematically searched for the literature describing COVID-19 reinfection published before 07 February 2022. The outcomes were the pooled incidence rate ratio (IRR) for estimating the risk of subsequent infection. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies. Statistical analyses were conducted using the R programming language 4.0.2. We identified 19 eligible studies including more than 3.5 million individuals without the history of COVID-19 vaccination. The efficacy of naturally acquired antibodies against reinfection was estimated at 84% (pooled IRR = 0.16, 95% CI: 0.14-0.18), with higher efficacy against symptomatic COVID-19 cases (pooled IRR = 0.09, 95% CI = 0.07-0.12) than asymptomatic infection (pooled IRR = 0.28, 95% CI = 0.14-0.54). In the subgroup analyses, the pooled IRRs of COVID-19 infection in health care workers (HCWs) and the general population were 0.22 (95% CI = 0.16-0.31) and 0.14 (95% CI = 0.12-0.17), respectively, with a significant difference (P = 0.02), and those in older (over 60 years) and younger (under 60 years) populations were 0.26 (95% CI = 0.15-0.48) and 0.16 (95% CI =  0.14-0.19), respectively. The risk of subsequent infection in the seropositive population appeared to increase slowly over time. In conclusion, naturally acquired antibodies against SARS-CoV-2 can significantly reduce the risk of subsequent infection, with a protection efficacy of 84%.Registration number: CRD42021286222.

Aerosol concentrations and size distributions during clinical dental procedures

Background

Suspected aerosol-generating dental instruments may cause risks for operators by transmitting pathogens, such as the SARS-CoV-2 virus. The aim of our study was to measure aerosol generation in various dental procedures in clinical settings.

Methods

The study population comprised of 84 patients who underwent 253 different dental procedures measured with Optical Particle Sizer in a dental office setting. Aerosol particles from 0.3 to 10 μm in diameter were measured. Dental procedures included oral examinations (N = 52), restorative procedures with air turbine handpiece (N = 8), high-speed (N = 6) and low-speed (N = 30) handpieces, ultrasonic scaling (N = 31), periodontal treatment using hand instruments (N = 60), endodontic treatment (N = 12), intraoral radiographs (N = 24), and dental local anesthesia (N = 31).

Results

Air turbine handpieces significantly elevated <1 μm particle median (p = 0.013) and maximum (p = 0.016) aerosol number concentrations as well as aerosol particle mass concentrations (p = 0.046 and p = 0.006) compared to the background aerosol levels preceding the operation. Low-speed dental handpieces elevated >5 μm median (p = 0.023), maximum (p = 0.013) particle number concentrations,> 5 μm particle mass concentrations (p = 0.021) and maximum total particle mass concentrations (p = 0.022). High-speed dental handpieces elevated aerosol concentration levels compared to the levels produced during oral examination.

Conclusions

Air turbine handpieces produced the highest levels of <1 μm aerosols and total particle number concentrations when compared to the other commonly used instruments. In addition, high- and low-speed dental handpieces and ultrasonic scalers elevated the aerosol concentration levels compared to the aerosol levels measured during oral examination. These aerosol-generating procedures, involving air turbine, high- and low-speed handpiece, and ultrasonic scaler, should be performed with caution.

Clinical significance

Aerosol generating dental instruments, especially air turbine, should be used with adequate precautions (rubber dam, high-volume evacuation, FFP-respirators), because aerosols can cause a potential risk for operators and substitution of air turbine for high-speed dental handpiece in poor epidemic situations should be considered to reduce the risk of aerosol transmission.

Risk of reinfection and disease after SARS-CoV-2 primary infection: Meta-analysis

INTRODUCTION

A precise estimate of the frequency and severity of SARS-CoV-2 reinfections would be critical to optimize restriction and vaccination policies for the hundreds of millions previously infected subjects. We performed a meta-analysis to evaluate the risk of reinfection and COVID-19 following primary infection.

METHODS

We searched MedLine, Scopus and preprint repositories for cohort studies evaluating the onset of new infections among baseline SARS-CoV-2-positive subjects. Random-effect meta-analyses of proportions were stratified by gender, exposure risk, vaccination status, viral strain, time between episodes, and reinfection definition.

RESULTS

Ninety-one studies, enrolling 15,034,624 subjects, were included. Overall, 158,478 reinfections were recorded, corresponding to a pooled rate of 0.97% (95% CI: 0.71%-1.27%), with no substantial differences by definition criteria, exposure risk or gender. Reinfection rates were still 0.66% after ≥12 months from first infection, and the risk was substantially lower among vaccinated subjects (0.32% vs. 0.74% for unvaccinated individuals). During the first 3 months of Omicron wave, the reinfection rates reached 3.31%. Overall rates of severe/lethal COVID-19 were very low (2-7 per 10,000 subjects according to definition criteria) and were not affected by strain predominance.

CONCLUSIONS

A strong natural immunity follows the primary infection and may last for more than one year, suggesting that the risk and health care needs of recovered subjects might be limited. Although the reinfection rates considerably increased during the Omicron wave, the risk of a secondary severe or lethal disease remained very low. The risk-benefit profile of multiple vaccine doses for this subset of population needs to be carefully evaluated.

COVID-19 incidence and vaccination rates among Canadian dental hygienists

BACKGROUND

Oral health care settings potentially carry a high risk of cross-infection due to close contact and aerosol-generating procedures. There is limited evidence of the impact of COVID-19 among dental hygienists. This longitudinal study aimed to 1) estimate COVID-19 incidence rates among Canadian dental hygienists over a 1-year period; and 2) estimate vaccination rates among Canadian dental hygienists.

METHODS

A prospective cohort study design was used to collect self-reported COVID-19 status from 876 registered dental hygienists across Canada via an online baseline survey and then 6 follow-up questionnaires delivered between December 2020 and January 2022. Bayesian Poisson and binomial models were used to estimate the incidence rate and cumulative incidence of self-reported COVID-19.

RESULTS

The estimated cumulative incidence of COVID-19 in dental hygienists in Canada from December 2020 to January 2022 was 2.39% (95% CrI, 1.49%-3.50%), while the estimated cumulative incidence of COVID-19 in corresponding Canadian provinces was 5.12% (95% CrI, 5.12%-5.13%) during the same period. At last follow-up, 89.4% of participants self-reported that they had received at least 1 dose of a COVID-19 vaccine.

CONCLUSION

The low infection rate observed among Canadian dental hygienists between December 2020 and January 2022 is reassuring to the dental hygiene and general community.

COVID-19 infection, and reinfection, and vaccine effectiveness against symptomatic infection among health care workers in the setting of omicron variant transmission in New Delhi, India

Background

Surge of SARS CoV-2 infections ascribed to omicron variant began in December 2021 in New Delhi. We determined the infection and reinfection density in a cohort of health care workers (HCWs) along with vaccine effectiveness (VE) against symptomatic infection within omicron transmission period (considered from December 01, 2021 to February 25, 2022.

Methods

This is an observational study from the All India Institute of Medical Sciences, New Delhi. Data were collected telephonically. Person-time at risk was counted from November 30, 2021 till date of infection/ reinfection, or date of interview. Comparison of clinical features and severity was done with previous pandemic periods. VE was estimated using test-negative case-control design [matched pairs (for age and sex)]. Vaccination status was compared and adjusted odds ratios (OR) were computed by conditional logistic regression. VE was estimated as (1-adjusted OR)X100-.

Findings

11474 HCWs participated in this study. The mean age was 36⋅2 (±10⋅7) years. Complete vaccination with two doses were reported by 9522 (83%) HCWs [8394 (88%) Covaxin and 1072 Covishield (11%)]. The incidence density of all infections and reinfection during the omicron transmission period was 34⋅8 [95% Confidence Interval (CI): 33⋅5-36⋅2] and 45⋅6 [95% CI: 42⋅9-48⋅5] per 10000 person days respectively. The infection was milder as compared to previous periods. VE was 52⋅5% (95% CI: 3⋅9-76⋅5, p = 0⋅036) for those who were tested within 14-60 days of receiving second dose and beyond this period (61-180 days), modest effect was observed.

Interpretation

Almost one-fifth of HCWs were infected with SARS CoV-2 during omicron transmission period, with predominant mild spectrum of COVID-19 disease. Waning effects of vaccine protection were noted with increase in time intervals since vaccination.

Funding

None.

Seroprevalence in health care workers during the later phase of the second wave: Results of three hospitals in Serbia, prior to vaccine administration

BACKGROUND

Since the COVID-19 pandemic has started, Serbia has faced problems in implementing proper public health measures in the population, including non-pharmaceutical interventions, as well as protecting health care workers (HCWs) from disease, like all other countries. This study aimed to estimate COVID-19 seroprevalence and evaluate the risk perception of COVID-19 among HCWs in three different hospitals in Belgrade, Serbia: non-COVID hospital, Emergency Center (EC), and dedicated COVID hospital.

METHODS

A cross-sectional study was conducted in three hospitals during the second wave of the outbreak in Serbia, from June to early October. All staff in these hospitals were invited to voluntarily participate in blood sampling for IgG antibodies against SARS-CoV-2 and questionnaire testing. The questionnaire included socio-demographic characteristics, known exposure to COVID-19 positive persons, previous signs and symptoms related to COVID-19 infection since the outbreak had started in our country, and SARS-CoV-2 PCR testing.

RESULTS

The overall prevalence of SARS-CoV-2 antibody among 1580 HCWs was 18.3 % [95 % CI 16.4-20.3 %]. Significantly higher prevalence of HCWs with positive results for the serum IgG antibody test was observed in COVID hospital (28.6 %, 95 %CI: 24.0-33.6 %) vs. prevalence in the EC (12.6 %, 95 %CI: 10.1-15.4 %), and in the non-COVID hospital (18.3 %, 95 %CI: 15.2-26.7 %). The prevalence adjusted for declared test sensitivity and specificity would be 16.8 %; that is 27.4 % in COVID-19 hospital, 10.9 % in EC, and 16.8 % in non-COVID hospital. In multivariate logistic regression analysis, the independent predictors for seropositivity were working in COVID-hospital, the profession of physician, and the presence of the following symptoms: fever, shortness of breath, and anosmia/ageusia.

CONCLUSIONS

We found an overall seropositivity rate of 18.3 % and 16.0 % of the adjusted rate that is higher than seroprevalence obtained in similar studies conducted before vaccinations started. The possibility that patients in non-COVID dedicated hospitals might also be infectious, although PCR tested, imposes the need for the use of personal protective equipment also in non-COVID medical institutions.

What Is the Antibody Response and Role in Conferring Natural Immunity After SARS-CoV-2 Infection? Rapid, Living Practice Points From the American College of Physicians (Version 2)

DESCRIPTION

The Scientific Medical Policy Committee (SMPC) of the American College of Physicians (ACP) developed these living, rapid practice points to summarize the current best available evidence on the antibody response to SARS-CoV-2 infection and protection against reinfection with SARS-CoV-2. This is version 2 of the ACP practice points, which serves to update version 1, published on 16 March 2021. These practice points do not evaluate vaccine-acquired immunity or cellular immunity.

METHODS

The SMPC developed this version of the living, rapid practice points based on an updated living, rapid, systematic review conducted by the Portland VA Research Foundation and funded by the Agency for Healthcare Research and Quality.

PRACTICE POINT 1

Do not use SARS-CoV-2 antibody tests for the diagnosis of SARS-CoV-2 infection.

PRACTICE POINT 2

Do not use SARS-CoV-2 antibody tests to predict the degree or duration of natural immunity conferred by antibodies against reinfection, including natural immunity against different variants.

RETIREMENT FROM LIVING STATUS

Although natural immunity remains a topic of scientific interest, this topic is being retired from living status given the availability of effective vaccines for SARS-CoV-2 and widespread recommendations for and prevalence of their use. Currently, vaccination is the best clinical recommendation for preventing infection, reinfection, and serious illness from SARS-CoV-2 and its variants.

Risk for Reinfection After SARS-CoV-2: A Living, Rapid Review for American College of Physicians Practice Points on the Role of the Antibody Response in Conferring Immunity Following SARS-CoV-2 Infection

BACKGROUND

The strength and duration of immunity from infection with SARS-CoV-2 are important for public health planning and clinical practice.

PURPOSE

To synthesize evidence on protection against reinfection after SARS-CoV-2 infection.

DATA SOURCES

MEDLINE (Ovid), the World Health Organization global literature database, ClinicalTrials.gov, COVID19reviews.org, and reference lists.

STUDY SELECTION

Longitudinal studies that compared the risk for reinfection after SARS-CoV-2 infection versus infection risk in individuals with no prior infection.

DATA EXTRACTION

Two investigators sequentially extracted study data and rated quality.

DATA SYNTHESIS

Across 18 eligible studies, reinfection risk ranged from 0% to 2.2%. In persons with recent SARS-CoV-2 infection compared with unvaccinated, previously uninfected individuals, 80% to 98% of symptomatic infections with wild-type or Alpha variants were prevented (high strength of evidence). In the meta-analysis, previous infection reduced risk for reinfection by 87% (95% CI, 84% to 90%), equaling 4.3 fewer infections per 100 persons in both the general population (risk difference, -0.043 [CI, -0.071 to -0.015]) and health care workers (risk difference, -0.043 [CI, -0.069 to -0.016]), and 26.6 fewer infections per 100 persons in care facilities (risk difference, -0.266 [CI, -0.449 to -0.083]). Protection remained above 80% for at least 7 months, but no study followed patients after the emergence of the Delta or Omicron variant. Results for the elderly were conflicting.

LIMITATION

Methods to ascertain and diagnose infections varied.

CONCLUSION

Before the emergence of the Delta and Omicron variants, persons with recent infection had strong protection against symptomatic reinfections for 7 months compared with unvaccinated, previously uninfected individuals. Protection in immunocompromised persons, racial and ethnic subgroups, and asymptomatic index case patients is unclear. The durability of protection in the setting of the Delta and Omicron variants is unknown.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (PROSPERO: CRD42020207098).

Evaluation of the analytical performance of anti-SARS-CoV-2 antibody test kits distributed or developed in Japan

Background: With the spread of COVID-19, anti-SARS-CoV-2 antibody tests have been utilized. Herein we evaluated the analytical performance of anti-SARS-CoV-2 antibody test kits using a new reference standard prepared from COVID-19 patient sera. Methods: Fifty-seven kits in total (16 immunochromatography types, 11 ELISA types and 30 types for automated analyzers) were examined. By measuring serially diluted reference standards, the maximum dilution factor showing a positive result and its precision were investigated. Results: The measured cut-off titers varied largely depending on the antibody kit; however, the variability was small, with the titers obtained by each kit being within twofold in most cases. Conclusion: The current results suggest that a suitable kit should be selected depending on the intended purpose.

SARS-CoV-2 seroprevalence in health care workers from 10 hospitals in Quebec, Canada: a cross-sectional study

BACKGROUND

The COVID-19 pandemic has disproportionately affected health care workers. We sought to estimate SARS-CoV-2 seroprevalence among hospital health care workers in Quebec, Canada, after the first wave of the pandemic and to explore factors associated with SARS-CoV-2 seropositivity.

METHODS

Between July 6 and Sept. 24, 2020, we enrolled health care workers from 10 hospitals, including 8 from a region with a high incidence of COVID-19 (the Montréal area) and 2 from low-incidence regions of Quebec. Eligible health care workers were physicians, nurses, orderlies and cleaning staff working in 4 types of care units (emergency department, intensive care unit, COVID-19 inpatient unit and non-COVID-19 inpatient unit). Participants completed a questionnaire and underwent SARS-CoV-2 serology testing. We identified factors independently associated with higher seroprevalence.

RESULTS

Among 2056 enrolled health care workers, 241 (11.7%) had positive SARS-CoV-2 serology. Of these, 171 (71.0%) had been previously diagnosed with COVID-19. Seroprevalence varied among hospitals, from 2.4% to 3.7% in low-incidence regions to 17.9% to 32.0% in hospitals with outbreaks involving 5 or more health care workers. Higher seroprevalence was associated with working in a hospital where outbreaks occurred (adjusted prevalence ratio 4.16, 95% confidence interval [CI] 2.63-6.57), being a nurse or nursing assistant (adjusted prevalence ratio 1.34, 95% CI 1.03-1.74) or an orderly (adjusted prevalence ratio 1.49, 95% CI 1.12-1.97), and Black or Hispanic ethnicity (adjusted prevalence ratio 1.41, 95% CI 1.13-1.76). Lower seroprevalence was associated with working in the intensive care unit (adjusted prevalence ratio 0.47, 95% CI 0.30-0.71) or the emergency department (adjusted prevalence ratio 0.61, 95% CI 0.39-0.98).

INTERPRETATION

Health care workers in Quebec hospitals were at high risk of SARS-CoV-2 infection, particularly in outbreak settings. More work is needed to better understand SARS-CoV-2 transmission dynamics in health care settings.

The burden of SARS-CoV-2 among healthcare workers across 16 hospitals of Kashmir, India-A seroepidemiological study

SARS-CoV-2 pandemic has greatly affected healthcare workers because of the high risk of getting infected. The present cross-sectional study measured SARS-CoV-2 antibody in healthcare workers of Kashmir, India.

METHODS

Serological testing to detect antibodies against nucleocapsid protein of SARS-CoV-2 was performed in 2003 healthcare workers who voluntarily participated in the study.

RESULTS

We report relatively high seropositivity of 26.8% (95% CI 24.8-28.8) for SARS-CoV-2in healthcare workers, nine months after the first case was detected in Kashmir. Most of the healthcare workers (71.7%) attributed infection to the workplace environment. Among healthcare workers who neither reported any prior symptom nor were they ever tested for infection by nasopharyngeal swab test, 25.5% were seropositive.

CONCLUSION

We advocate interval testing by nasopharyngeal swab test of all healthcare workers regardless of symptoms to limit the transmission of infection within healthcare settings.

Genetic epidemiology of SARS-CoV-2 transmission in renal dialysis units - A high risk community-hospital interface

OBJECTIVES

Patients requiring haemodialysis are at increased risk of serious illness with SARS-CoV-2 infection. To improve the understanding of transmission risks in six Scottish renal dialysis units, we utilised the rapid whole-genome sequencing data generated by the COG-UK consortium.

METHODS

We combined geographical, temporal and genomic sequence data from the community and hospital to estimate the probability of infection originating from within the dialysis unit, the hospital or the community using Bayesian statistical modelling and compared these results to the details of epidemiological investigations.

RESULTS

Of 671 patients, 60 (8.9%) became infected with SARS-CoV-2, of whom 16 (27%) died. Within-unit and community transmission were both evident and an instance of transmission from the wider hospital setting was also demonstrated.

CONCLUSIONS

Near-real-time SARS-CoV-2 sequencing data can facilitate tailored infection prevention and control measures, which can be targeted at reducing risk in these settings.

Contribution of rapid lateral flow assays from capillary blood specimens to the diagnosis of COVID-19 in symptomatic healthcare workers: a pilot study in a university hospital, Paris, France

Background

This study aimed to assess, by rapid tests, the immune status against COVID-19 among Healthcare Workers (HCW) with history of symptoms, and for whom SARS-CoV-2 detection was either not documented or negative.

Methods

Whole blood by finger prick and serum samples were taken from HCW for use with 2 rapid lateral flow tests and an automated immunoassay.

Results

Seventy-two HCWs were included, median duration between symptoms onset and serology sampling was 68 days. Anti-SARS-CoV-2 antibodies were detected by rapid test in 11 HCW (15.3%) and confirmed in the 10 with available serum by the automated immunoassay. The frequency of ageusia or anosmia was higher in participants with SARS-CoV-2 antibodies (P = 0.0006 and P = 0.029, respectively).

Conclusions

This study, among symptomatic HCW during the first wave in France, showed that 15% had IgG anti-SARS-CoV-2, a higher seroprevalence than in the general population. Rapid lateral flow tests were highly concordant with automated immunoassay.