Effectiveness of inactivated COVID-19 vaccines against SARS-CoV-2 infections among healthcare personnel in Pakistan: a test-negative case-control study.

OBJECTIVE: During the COVID-19 pandemic, several vaccines that were efficacious in randomised controlled trials were authorised for mass vaccination. In developing countries, inactivated vaccines were widely administered. While inactivated vaccines have been deemed effective in reducing disease severity, for healthcare personnel (HCP), effectiveness against SARS-CoV-2 infections is essential to reduce the risk to vulnerable patients and ensure a stable healthcare workforce. There are limited studies examining inactivated vaccines' effectiveness against SARS-CoV-2 variants of concern (VOCs) in real-world settings. We estimated the effectiveness of inactivated vaccines (BBIBP-CorV and CoronaVac) against reverse transcription PCR (RT-PCR)-confirmed SARS-CoV-2 infections among HCP in the setting of emerging SARS-CoV-2 VOCs in Pakistan. DESIGN: A retrospective matched, test-negative case-control analysis using existing data from an Employee Health database on HCP at a large, private healthcare system in Pakistan. PARTICIPANTS: 4599 HCP were tested between 1 April and 30 September 2021. Each case (PCR positive) was matched to two to six controls (PCR negative) by the date of the RT-PCR test (±7 days) to reduce bias. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was vaccine effectiveness (VE) against SARS-CoV-2 infection. The secondary outcome was VE against symptomatic SARS-CoV-2 infection. Per cent VE was calculated using (1-OR)*100, with the OR of getting a PCR-confirmed SARS-COV-2 infection estimated using conditional logistic regression, after adjusting for age, gender, work area and history of SARS-CoV-2 infection. RESULTS: Inactivated vaccines were ineffective against SARS-CoV-2 infections after receiving the first dose (VE 17%, 95% CI -10, 39; p=0.261). They showed modest effectiveness ≥14 days after the second dose against SARS-CoV-2 infections (VE 30%, 95% CI 7, 48; p=0.015) and symptomatic SARS-CoV-2 infections (VE 33%, 95% CI 6, 52; p=0.002). CONCLUSIONS: Inactivated vaccines show modest effectiveness against SARS-CoV-2 infections in the setting of emerging VOCs. This builds a strong case for boosters and/or additional vaccination.

Using rapid antigen testing for early, safe return-to-work for healthcare personnel after SARS-CoV-2 infection in a healthcare system in Pakistan: A retrospective cross-sectional study.

Anticipating staff shortage during the Omicron variant surge, we modified the US Centers for Disease Control and Prevention's contingency guidelines at a healthcare system in Pakistan. Infected staff had a SARS-CoV-2 rapid antigen test after 5-7 days of isolation, to decide a safe return-to-work. This led to signifcant cost savings without compromising patient/staff safety.

Does the CDC COVID-19 Exposure Assessment Criteria for Healthcare Personnel Work in a Healthcare Setting in Pakistan?

OBJECTIVE: To evaluate the real-world performance of the CDC's "Interim US guidance for risk assessment and work restriction for healthcare personnel with exposure to COVID-19" at a private healthcare system in Pakistan. STUDY DESIGN: Retrospective observational study. PLACE AND DURATION OF STUDY: The Aga khan University Hospital, Karachi, and its associated healthcare facilities in all four provinces of Pakistan, from February to September 2020. METHODOLOGY: Healthcare personnel (HCPs) assessed and tested for exposures to COVID-19 were included in the study. An exposure category was assigned to each HCP presenting with exposure to COVID-19 based on the CDC criteria. Percentage positivity was recorded and compared among the different exposure categories. Logistic regression analysis was used to identify variables significantly associated with COVID-19 infection. RESULTS: Three thousand Six hundred and forty-seven HCPs were assessed for exposure to COVID-19 of whom 603 (16.5%) tested positive. Percent positivity was highest in high-risk symptomatic HCPs (18.2%), 15.6% in low-risk symptomatic HCPs, and 11% in high-risk asymptomatic HCPs. After controlling for age, gender, area of work, and source of exposure, compared to low-risk asymptomatic HCPs, the odds of a positive SARS-CoV-2 PCR were 2.13 (95%CI: 1.49-3.04) for high-risk symptomatic, 1.66 (95% CI: 1.12-2.46) for low-risk symptomatic, and 1.18 (95% CI: 0.83-1.68) for high-risk asymptomatic HCPs. CONCLUSION: Regardless of exposure category, HCPs with symptoms consistent with COVID-19 have the highest likelihood of testing positive. The CDC exposure risk assessment criteria work best for symptomatic HCPs. Testing asymptomatic HCPs with high-risk exposures may not be necessary in low-resource settings with a limited healthcare workforce. KEY WORDS: COVID-19, Employee health, Occupational health and safety programs, Medical surveillance/screening, Return to work.