SARS-CoV-2 antibody detection in skilled nursing facility residents

SARS-CoV-2 Seropositivity in Nursing Home Staff and Residents during the First SARS-CoV-2 Wave in Flanders, Belgium

(1) Background: early in the COVID-19 pandemic, reverse transcription polymerase chain reaction (RT-PCR) testing was limited. Assessing seroprevalence helps understand prevalence and reinfection risk. However, such data are lacking for the first epidemic wave in Belgian nursing homes. Therefore, we assessed SARS-CoV-2 seroprevalence and cumulative RT-PCR positivity in Belgian nursing homes and evaluated reinfection risk. (2) Methods: we performed a cross-sectional study in nine nursing homes in April and May 2020. Odds ratios (ORs) were calculated to compare the odds of (re)infection between seropositive and seronegative participants. (3) Results: seroprevalence was 21% (95% CI: 18-23): 22% (95% CI: 18-25) in residents and 20% (95% CI: 17-24) in staff. By 20 May 2020, cumulative RT-PCR positivity was 16% (95% CI: 13-21) in residents and 8% (95% CI: 6-12) in staff. ORs for (re)infection in seropositive (compared to seronegative) residents and staff were 0.22 (95% CI: 0.06-0.72) and 3.15 (95% CI: 1.56-6.63), respectively. (4) Conclusion: during the first wave, RT-PCR test programmes underestimated the number of COVID-19 cases. The reinfection rate in residents was 3%, indicating protection, while it was 21% in staff, potentially due to less cautious health behaviour. Future outbreaks should use both RT-PCR and serological testing for complementary insights into transmission dynamics.

Impact of the COVID-19 pandemic and corresponding control measures on long-term care facilities: a systematic review and meta-analysis

BACKGROUND

Long-term care facilities (LTCFs) were high-risk settings for COVID-19 outbreaks.

OBJECTIVE

To assess the impacts of the COVID-19 pandemic on LTCFs, including rates of infection, hospitalisation, case fatality, and mortality, and to determine the association between control measures and SARS-CoV-2 infection rates in residents and staff.

METHOD

We conducted a systematic search of six databases for articles published between December 2019 and 5 November 2021, and performed meta-analyses and subgroup analyses to identify the impact of COVID-19 on LTCFs and the association between control measures and infection rate.

RESULTS

We included 108 studies from 19 countries. These studies included 1,902,044 residents and 255,498 staff from 81,572 LTCFs, among whom 296,024 residents and 36,807 staff were confirmed SARS-CoV-2 positive. The pooled infection rate was 32.63% (95%CI: 30.29 ~ 34.96%) for residents, whereas it was 10.33% (95%CI: 9.46 ~ 11.21%) for staff. In LTCFs that cancelled visits, new patient admissions, communal dining and group activities, and vaccinations, infection rates in residents and staff were lower than the global rate. We reported the residents' hospitalisation rate to be 29.09% (95%CI: 25.73 ~ 32.46%), with a case-fatality rate of 22.71% (95%CI: 21.31 ~ 24.11%) and mortality rate of 15.81% (95%CI: 14.32 ~ 17.30%). Significant publication biases were observed in the residents' case-fatality rate and the staff infection rate, but not in the infection, hospitalisation, or mortality rate of residents.

CONCLUSION

SARS-CoV-2 infection rates would be very high among LTCF residents and staff without appropriate control measures. Cancelling visits, communal dining and group activities, restricting new admissions, and increasing vaccination would significantly reduce the infection rates.

Descriptive evaluation of antibody responses to severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection in plasma and gingival crevicular fluid in a nursing home cohort-Arkansas, June-August 2020

OBJECTIVE

To characterize and compare severe acute respiratory coronavirus virus 2 (SARS-CoV-2)-specific immune responses in plasma and gingival crevicular fluid (GCF) from nursing home residents during and after natural infection.

DESIGN

Prospective cohort.

SETTING

Nursing home.

PARTICIPANTS

SARS-CoV-2-infected nursing home residents.

METHODS

A convenience sample of 14 SARS-CoV-2-infected nursing home residents, enrolled 4-13 days after real-time reverse transcription polymerase chain reaction diagnosis, were followed for 42 days. After diagnosis, plasma SARS-CoV-2-specific pan-Immunoglobulin (Ig), IgG, IgA, IgM, and neutralizing antibodies were measured at 5 time points, and GCF SARS-CoV-2-specific IgG and IgA were measured at 4 time points.

RESULTS

All participants demonstrated immune responses to SARS-CoV-2 infection. Among 12 phlebotomized participants, plasma was positive for pan-Ig and IgG in all 12 participants. Neutralizing antibodies were positive in 11 participants; IgM was positive in 10 participants, and IgA was positive in 9 participants. Among 14 participants with GCF specimens, GCF was positive for IgG in 13 participants and for IgA in 12 participants. Immunoglobulin responses in plasma and GCF had similar kinetics; median times to peak antibody response were similar across specimen types (4 weeks for IgG; 3 weeks for IgA). Participants with pan-Ig, IgG, and IgA detected in plasma and GCF IgG remained positive throughout this evaluation, 46-55 days after diagnosis. All participants were viral-culture negative by the first detection of antibodies.

CONCLUSIONS

Nursing home residents had detectable SARS-CoV-2 antibodies in plasma and GCF after infection. Kinetics of antibodies detected in GCF mirrored those from plasma. Noninvasive GCF may be useful for detecting and monitoring immunologic responses in populations unable or unwilling to be phlebotomized.

Longitudinal serologic and viral testing post-SARS-CoV-2 infection and post-receipt of mRNA COVID-19 vaccine in a nursing home cohort-Georgia, October 2020‒April 2021

There are limited data describing SARS-CoV-2-specific immune responses and their durability following infection and vaccination in nursing home residents. We conducted a prospective longitudinal evaluation of 11 consenting SARS-CoV-2-positive nursing home residents to evaluate the quantitative titers and durability of binding antibodies detected after SARS-CoV-2 infection and subsequent COVID-19 vaccination. The evaluation included nine visits over 150 days from October 25, 2020, through April 1, 2021. Visits included questionnaire administration, blood collection for serology, and paired anterior nasal specimen collection for testing by BinaxNOW™ COVID-19 Ag Card (BinaxNOW), reverse transcription polymerase chain reaction (RT-PCR), and viral culture. We evaluated quantitative titers of binding SARS-CoV-2 antibodies post-infection and post-vaccination (beginning after the first dose of the primary series). The median age among participants was 74 years; one participant was immunocompromised. Of 10 participants with post-infection serology results, 9 (90%) had detectable Pan-Ig, IgG, and IgA antibodies, and 8 (80%) had detectable IgM antibodies. At first antibody detection post-infection, two-thirds (6/9, 67%) of participants were RT-PCR-positive, but none were culture- positive. Ten participants received vaccination; all had detectable Pan-Ig, IgG, and IgA antibodies through their final observation ≤90 days post-first dose. Post-vaccination geometric means of IgG titers were 10-200-fold higher than post-infection. Nursing home residents in this cohort mounted robust immune responses to SARS-CoV-2 post-infection and post-vaccination. The augmented antibody responses post-vaccination are potential indicators of enhanced protection that vaccination may confer on previously infected nursing home residents.

Factors Affecting SARS-CoV-2 Test Discordance in Skilled Nursing Facilities

OBJECTIVES

Reverse transcription polymerase chain reaction (PCR) and antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are sometimes discordant. We evaluated the discordance between antigen and PCR tests sampled in skilled nursing facilities (SNFs) to assess the relationship of symptom presence, timing between tests, and the presence of a facility outbreak.

DESIGN

Observational study using electronic health record data.

SETTING AND PARTICIPANTS

Residents of 306 SNFs in 23 states, operated by 1 company.

METHODS

We identified all rapid antigen and PCR tests conducted in study SNFs as of January 10, 2021, and classified whether symptoms were present and whether the facility was in outbreak at time of testing. We calculated the proportions of antigen tests with discordant follow-up PCR results conducted no more than 2 days after the antigen test.

RESULTS

Of the 171,280 antigen tests in 34,437 SNF residents, 20,991 (12.3%) were followed by a PCR test within 2 days. A total of 1324 negative antigen tests were followed by a positive PCR result, representing 0.8% of all antigen tests and 6.3% of repeated antigen tests; while 337 positive antigen tests were followed by a negative PCR result, representing 0.2% of all antigen tests and 1.6% of repeated antigen tests. Discordance more often occurred when residents were symptomatic at time of antigen testing, during known facility outbreaks, and when the antigen test was compared with a PCR test done within 2 days vs 1 day.

CONCLUSIONS AND IMPLICATIONS

Overall, discordance between SARS-CoV-2 antigen and PCR tests was low. Discordance was more common when the individual was symptomatic at time of antigen testing and during facility outbreaks. This suggests that a testing strategy which couples widespread use of antigen tests with clinical thresholds to conduct follow-up confirmatory PCR testing appears to perform well in SNFs, where timely and accurate SARS-CoV-2 case identification are critical.

Electronic Health Records to Rapidly Assess Biosimilar Uptake: An Example Using Insulin Glargine in a Large U.S. Nursing Home Cohort

Large healthcare administrative databases, like Medicare claims, are a common means to evaluate drug policies. However, administrative data often have a lag time of months to years before they are available to researchers and decision-makers. Therefore, administrative data are not always ideal for timely policy evaluations. Other sources of data are needed to rapidly evaluate policy changes and inform subsequent studies that utilize large administrative data once available. An emerging area of interest in both pharmacoepidemiology and drug policy research that can benefit from rapid data availability is biosimilar uptake, due to the potential for substantial cost savings. To respond to the need for such a data source, we established a public-private partnership to create a near-real-time database of over 1,000 nursing homes’ electronic health records to describe and quantify the effects of recent policies related to COVID-19 and medications. In this article, we first describe the components and infrastructure used to create our EHR database. Then, we provide an example that illustrates the use of this database by describing the uptake of insulin glargine-yfgn, a new exchangeable biosimilar for insulin glargine, in US nursing homes. We also examine the uptake of all biosimilars in nursing homes before and after the onset of the COVID-19 pandemic. We conclude with potential directions for future research and database infrastructure.

Short-term impact of nursing home SARS-CoV-2 vaccinations on new infections, hospitalizations, and deaths

Objective

To compare rates of incident SARS‐CoV‐2 infection and 30‐day hospitalization or death among residents with confirmed infection in nursing homes with earlier versus later SARS‐CoV‐2 vaccine clinics.

Design

Matched pairs analysis of nursing homes that had their initial vaccine clinics between December 18, 2020, and January 2, 2021, versus between January 3, 2021, and January 18, 2021. Matched facilities had their initial vaccine clinics between 12 and 16 days apart.

Setting and Participants

Two hundred and eighty nursing homes in 21 states owned and operated by the largest long‐term care provider in the United States.

Measurements

Incident SARS‐CoV‐2 infections per 100 at‐risk residents per week; hospital transfers and/or deaths per 100 residents with confirmed SARS‐CoV‐2 infection per day, averaged over a week.

Results

The early vaccinated group included 136 facilities with 12,157 residents; the late vaccinated group included 144 facilities with 13,221 residents. After 1 week, early vaccinated facilities had a predicted 2.5 fewer incident SARS‐CoV‐2 infections per 100 at‐risk residents per week (95% CI: 1.2–4.0) compared with what would have been expected based on the experience of the late vaccinated facilities. The rates remained significantly lower for several weeks. Cumulatively over 5 weeks, the predicted reduction in new infections was 5.2 cases per 100 at‐risk residents (95% CI: 3.2–7.3). By 5 to 8 weeks post‐vaccine clinic, early vaccinated facilities had a predicted 1.1 to 3.8 fewer hospitalizations and/or deaths per 100 infected residents per day, averaged by week than expected based on late vaccinated facilities' experience for a cumulative on average difference of 5 events per 100 infected residents per day.

Conclusions

The SARS‐CoV‐2 vaccines seem to have accelerated the rate of decline of incident infections, morbidity, and mortality in this large multi‐state nursing home population.

See related editorial by Ouslander et al and related articles by Moore et al, Rudolph et al, and Domi et al. in this issue.