Questionnaire-based vs universal PCR testing for SARS-CoV-2 in women admitted for delivery

DNA amplification tests at universal pre-admission screening with enhanced precaution strategies for asymptomatic patients with COVID-19

Objective

To analyse the effect of hospital pre-admission screening and enhanced precaution strategies on the transmission of severe acute respiratory syndrome coronavirus-2.

Methods

This retrospective cohort study was conducted over 17 months from 11 May 2020 to 30 September 2021 at a large hospital in Tokyo. Universal DNA amplification tests were conducted during pre-admission screening, and enhanced precaution strategies were implemented for all patients with negative admission tests. The primary outcome was the occurrence of symptomatic coronavirus disease 2019 (COVID-19) in patients after admission. The secondary outcomes were time-series analyses of monthly positive admission test numbers, positive rates, clinical features in positive cases, and clinically confirmed nosocomial transmission.

Results

In total, 32,081 patients were screened pre-admission (29,556 asymptomatic patients and 2525 symptomatic patients). Of the asymptomatic patients, 0.11% (n=32) tested positive and were admitted to a designated COVID-19 ward or were not admitted. Among the five inpatients who developed symptomatic COVID-19 during hospitalization, only two cases were related to a single nosocomial transmission.

Conclusion

Pre-admission test screening was effective in identifying asymptomatic cases of COVID-19. This allowed administrators to quarantine patients or delay hospital admission. The combination of testing and enhanced precaution strategies for asymptomatic cases of COVID-19 may minimize nosocomial transmission.

Comparing Two Testing Strategies: Universal versus Symptomatic SARS-CoV-2 Testing in Obstetric Patients

OBJECTIVE

To compare universal severe acute respiratory syndrome coronvirus-2 (SARS-CoV-2) testing to symptomatic testing at two large academic centers.

STUDY DESIGN

We performed a retrospective cohort study comparing the approach to testing at two academic centers in Northeast Ohio. The study period started with the inception of symptomatic testing for SARS-CoV-2 at both institutions in March 2020. Women younger than 18 years were excluded. The primary outcome was the SARS-CoV-2 positivity rate in symptomatic pregnant patients at both institutions. Our coprimary outcome was the additional positivity rate obtained from universal testing at the University Hospitals. The secondary outcome of interest was the percentage of SARS-CoV-2 screen positive mothers with screen positive neonates. Data were analyzed using Mann-Whitney U test for continuous variables with chi-square and Fisher's exact tests for proportions.

RESULTS

During the study period, 144 pregnant women with symptoms of coronavirus disease 2019 (COVID-19) were tested at MetroHealth of which 27 resulted as positive for SARS-CoV-2 (18.7% positivity rate). University Hospitals tested 392 pregnant women with symptoms of COVID-19 of which 67 resulted as positive for SARS-CoV-2 (positivity rate 17.0%). In the universal testing program at University Hospitals, an additional 2,870 tests were performed on asymptomatic pregnant women of which 30 were positive for SARS-CoV-2 (1.0% positivity rate).There were no SARS-CoV-2 positive infants in our cohort, and all cases of maternal critical illness occurred in symptomatic patients.

CONCLUSION

Universal and symptomatic testing approaches demonstrated similar clinical performance within a single geographic region in obstetric patients.

KEY POINTS

· There is a lack of data to recommend an optimal approach to SARS-CoV-2 testing in obstetric patients.. · Universal testing detected few additional cases of SARS-CoV-2.. · Maternal and neonatal outcomes were unaffected by testing strategy..

Prevalence of SARS-CoV-2 infection among obstetric patients in Ottawa, Canada: a descriptive study

BACKGROUND

There is limited information on the prevalence of SARS-CoV-2 infection in obstetric settings in Canada, beyond the first wave of the COVID-19 pandemic (February to June 2020). We sought to describe the prevalence of SARS-CoV-2 infection in pregnant people admitted to triage units at a tertiary care hospital in Ottawa, Canada.

METHODS

We conducted a descriptive study of pregnant people admitted to obstetric triage assessment units at The Ottawa Hospital between Oct. 19 and Nov. 27, 2020 (second local wave of the COVID-19 pandemic). Participants underwent SARS-CoV-2 polymerase chain reaction (PCR) (via naso- or oropharyngeal swabs) and serology testing upon admission. We excluded individuals younger than 18 years, those who did not speak English or French, those who enrolled in conflicting studies, those admitted for pregnancy termination and those triaged between 11:31 pm and 7:29 am. Swab and serology samples were analyzed using digital droplet PCR and enzyme-linked immunosorbent assays, respectively. We defined SARS-CoV-2 seropositivity as a positive result for immunoglobulin (Ig) G, either alone or in combination with IgM or IgA.

RESULTS

Of the 632 eligible patients, 363 (57.4%) consented to participation and 362 collectively provided 284 swab and 352 blood samples eligible for analysis. Common reasons for declining participation included feeling overwhelmed or anxious, being worried about repercussions of testing, pain or discomfort with testing or disinterest in research. Participants were mostly multiparous (53.9%) and in their third trimester upon admission (88.4%). In all, 18 (4.9%) participants had evidence of SARS-CoV-2 exposure; 2 (0.7%) of 284 were positive for SARS-CoV-2 by PCR and 16 (4.5%) of 352 were positive for IgG antibodies to SARS-CoV-2.

INTERPRETATION

During the second local wave of the COVID-19 pandemic, the prevalence of active SARS-CoV-2 infection among obstetric patients in Ottawa was 0.7% and seroprevalence was 4.5%. Our low participation rate highlights the need for improvements in patient education and public health messaging on the benefits of SARS-CoV-2 testing programs.

Universal Testing Policy for COVID-19 in Pregnancy: A Systematic Review

Background

The coronavirus disease (COVID-19) has spread at an accelerated rate. WHO reported that in the general population, the majority are either asymptomatic or mildly infected. In view of the high risk of SARS-CoV-2 transmission from a pregnant woman to her newborn, healthcare workers and other patients, it is a raised concern whether universal testing should be implemented in this targeted population. The current guidelines have not recommended a universal testing policy. In certain European countries, however, the policy was implemented by some hospitals in regions with high prevalence of COVID-19 infection.

Aim(s)

To assess the justification for universal screening of pregnant women for COVID-19 prior to admission in labor through systematic review of antenatal prevalence of asymptomatic infection, hence risk of inadvertent spread of infection.

Materials and Methods

Three databases confined to PubMed, Ovid and Science Direct were used to search for articles from November 2019 onwards published in the English language. The search was conducted using the keywords “COVID-19” or “coronavirus” or “SARS-CoV-2” and “pregnancy” or “pregnant” or “obstetric” or “labor” and “universal” or “testing” or “prevalence”. The review was registered with PROSPERO.

Results

The search result retrieved 34 studies, with the majority consisting of retrospective cohort studies, while other studies such as prospective cohort study, research letters and a case series were also identified. A total of 19,958 pregnant women were universally tested until the date of report. Overall, the prevalence of universal testing among pregnant women presenting to labor and delivery units are higher in Western regions. From the total number of pregnant women 5.3% tested positive and among these, the majority (75.5%) did not manifest any symptoms at the time of testing.

Conclusion

In areas with high prevalence of COVID-19 infection, the implementation of a universal testing policy among pregnant women presenting to labor and admission units may be cost effective in helping to curb disease transmission.

Systematic Trial Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020184248, PROSPERO: CRD42020184248.