COVID-19 BREAKTHROUGH CASES AMONG SPUTNIK V VACCINATED HEALTH CARE WORKERS AT A UNIVERSITY HOSPITAL IN BUENOS AIRES, ARGENTINA

DIAZ VICTORIA; HERMIDA ELIANA; MARTIN E. STRYJEWSKI; RODRIGUEZ PAMELA ELIZABETH; JARA RAQUEL; GUADALUPE CARBALLAL; REYES, NOELIA SOLEDAD; SCHWALD ISABEL; ANA CEBALLOS; ECHAVARRIA MARCELA

Simposio; 36th Clinical Virology Symposium.; 2022

BackgroundBreakthrough cases of SARS-CoV-2 (detection of in a respiratory specimen ≥14 days after completedCOVID-19 vaccine doses) have been reported in less than 1% of subjects vaccinated with mRNAvaccines in US. Data regarding breakthrough cases in countries with high SARS-CoV-2 positivity rateis scarce, particularly in countries vaccinating with Sputnik V. Here we report breakthrough casesamong health care workers (HCW) fully vaccinated with Sputnik V vaccine in Argentina.Materials and MethodsAs part of an ongoing prospective study on humoral responses to SARS-CoV-2, HCW from CEMICUniversity Hospital in Buenos Aires, Argentina, who were fully vaccinated with SputnikV (SV)vaccine, were followed. Humoral response (anti Spike and anti RBD IgG) was determined by ELISA(COVIDAR). Neutralizing antibodies response was studied. Subjects who developed COVID-19symptoms were diagnosed by RT-PCR (Echavarria et al, 2021). Sequencing of Spike protein was usedto determine variants (Paden et al, 2020).ResultsDuring this studied period, the general SARS-CoV-2 positivity rate in Buenos Aires was 35%. FromMarch 2021 to January 2022 a total of 125 HCW fully vaccinated with Sputnik V were enrolled.Among them 75 (60%) were female and the mean age was 41 years old (IQR 34-51 years old).Twenty one individuals (16%) developed mild COVID-19. Most of them were female (75%), meanage was 39 years old (IQR, 25-50 years old) and 9 (38.1%) had comorbidities. Median time fromsecond vaccine dose to SARS-CoV-2-diagnosis was 153 days (IQR 73-292). Serum samples obtainedfrom 21 individuals before developing COVID showed that most of them (90%) had anti-spike IgG.Median neutralizing antibody title of in 9 patients was 16 (range: 4-64).Sequencing performed in 9 patients, showed that 6 had SARS-CoV-2 Gamma variant (Manaosvariant) and 3 had Lambda variant (Andina variant).New breakthrough cases are currently increasing.ConclusionsIn a cohort of HCW fully vaccinated with Sputnik V breakthrough cases of SARS-CoV-2 during highviral circulation was 16%. Most HCW had anti-spike IgG in response to vaccination and beforedeveloping mild COVID-19.