375 - High laboratory-confirmed SARS-CoV-2 attack rate in Lima health care personnel during August 2020-March 2021 suggests role for improved infection control

Background: Peru has one of the highest per capita SARS-CoV-2 death rates in Latin America. Healthcare workers (HCW) are a critical workforce during the COVID-19 pandemic but are themselves often at increased risk of infection. We evaluated SARS-CoV-2 attack rate and risk factors among frontline HCWs.

Methods: We performed a prospective cohort study of HCW serving two acute care hospitals in Lima, Peru from Aug 2020 to Mar 2021. Participants had baseline SARS-CoV-2 serology using the CDC ELISA, active symptom monitoring, and weekly respiratory specimen collection with COVID-19 exposure/risk assessment for 16-weeks regardless of symptoms. Respiratory specimens were tested by real-time reverse transcriptase PCR (rRT-PCR).

Results: Of 783 eligible, 667 (85%) HCW were enrolled (33% nurse assistants, 29% non-clinical staff, 26% nurses, 7% physicians, and 6% other). At baseline and prior to COVID-19 vaccine introduction, 214 (32.1%; 214/667) were reactive for SARS-CoV-2 antibodies. In total, 72 (10.8%; 72/667) HCWs were found to be rRT-PCR positive during weekly follow-up. Of the rRT-PCR positive HCWs, 37.5% (27/72) did not report symptoms within 1-week of specimen collection. During follow up, HCW without detectable SARS-CoV-2 antibodies at baseline were significantly more likely to be rRT-PCR positive (65/453, 14.3%) compared to those with SARS-CoV-2 antibodies at baseline (4/214, 1.9%) (p-value: < 0.001). Three HCW were both serologically reactive and rRT-PCR positive at baseline. Looking only at HCW without SARS-CoV-2 antibodies, nurse assistants (rRT-PCR positive: 18.6%; 27/141) and non-clinical healthcare workers (16.5%; 21/127) were at greater risk of infection compared to nurses (8.5%; 10/118), physicians (7.9%; 3/38), and other staff (10.3%; 4/29) (RR 1.95;95%CI 1.2,3.3; p-value: 0.01).

Conclusion:

Baseline SARS-CoV-2 prevalence and 16-week cumulative incidence were substantial in this pre-vaccination Peruvian HCW cohort. Almost 40% of new infections occurred in HCW without complaint of symptoms illustrating a limitation of symptom-based HCW screening for COVID-19 prevention. Nurse assistants and non-clinical healthcare workers were at greater risk of infection indicating a role for focused infection prevention and risk reduction strategies for some groups of HCW.

Presenting Author(s)

MW

Matthew Westercamp, PhD

Epidemiologist
Centers for Disease Control and Prevention
Atlanta, Georgia, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Co-Author(s)

GS

Giselle Soto, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Rachel Mann Smith, MD, MPH

Surveillance Team Lead
Centers for Disease Control and Prevention
Decatur, Georgia, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
EA

Eduardo Azziz-Baumgartner, MD, MPH

Medical Officer
Centers for Disease Control and Prevention
Atlanta, GA, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
SB

Susan Bollinger, MPH, MT(ASCP)

Microbiologist
U.S. Centers for Disease Control and Prevention
Atlanta, Georgia, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
RC

Roger Castillo, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
AL

Alejandro Llanos Cuentas, MD, PhD

Hospital Nacional Cayetano Heredia
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
MG

Max Grogl, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
NO

Natalie Olson, n/a

U.S. Centers for Disease Control and Prevention – Influenza Division
Atlanta, Georgia, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
MP

Mike Prouty, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
EM

Eduardo Matos, n/a

Hospital Nacional Arzobispo Loayza
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
CR

Candice Romero, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
MS

Marita Silva, n/a

U.S. Naval Medical Research Unit No. 6
Lima, Lima, Peru
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Fernanda C. Lessa, MD, MPH

Medical Epidemiologist
Centers for Disease Control and Prevention, Atlanta, GA, USA
Atlanta, GA, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
CA

Carmen S. Arriola, DVM, PhD

Epidemiologist
Centers for Disease Control and Prevention
Atlanta, GA, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.