key: cord-1031358-sbrk9lla authors: Luna-Muschi, Alessandra; Borges, Igor C.; de Faria, Elizabeth; Barboza, Antonio S.; Maia, Fernando L.; Leme, Mariana D.; Guedes, Ana Rubia; Mendes-Correa, Maria Cassia; Kallas, Esper G.; Segurado, Aluísio C.; Duarte, Alberto J.S.; Lazari, Carolina S.; Andrade, Pamela S.; Sales, Flávia C.S.; Claro, Ingra M.; Sabino, Ester C.; Levin, Anna S.; Costa, Silvia F. title: Clinical features of COVID-19 by SARS-CoV-2 Gamma variant: a prospective cohort study of vaccinated and unvaccinated healthcare workers date: 2021-09-16 journal: J Infect DOI: 10.1016/j.jinf.2021.09.005 sha: a306a8d8c4dc8bb2af52041fc0b58a0f84071048 doc_id: 1031358 cord_uid: sbrk9lla nan Services and tested using RT-PCR for SARS-CoV-2. We aimed to characterize the clinical features of COVID-19 caused by the Gamma variant in comparison with strains that were not variants of concern (non-VoC). In this prospective cohort we included symptomatic COVID-19 cases among HCW from January 22 to May 15, 2021. All positive samples for SARS-CoV-2 RT-PCR underwent whole genome sequencing using the MinION platform (additional details on supplementary material). 3,4 Clinical data were collected using a structured data formulary. Proportions and medians were compared using the chi-square test and Mann-Whitney U test. Risk factors for Gamma variant infection were evaluated using a multivariate logistic regression with COVID-19 immunization, previous COVID-19, age, and month of diagnosis as independent variables. Risk factors for the presence of COVID-19 symptoms on diagnosis were evaluated using a multivariate logistic regression including Gamma variant infection, COVID-19 immunization, previous COVID-19, duration of symptoms on diagnosis, sex, and age as independent variables. Since we evaluated risk factors for 11 symptoms, these analyses were adjusted for multiple comparisons according to Bonferroni's correction. A HCW was considered to be fully immunized after at least 14 days after the second dose of any COVID-19 vaccine. Statistical analyses were two-tailed with an alpha error of 0.05. The software SPSS (version 17.0) and R (version 4.1.0) were used for the analyses. This study was approved by the Hospital's Ethics Committee (CAAE:42708721.0.0000.0068). During the study period there were 523 symptomatic COVID-19 cases among HCW and 423 of them were included in the study, of which 415 (98%) had mild disease (Table 1 In the unadjusted bivariate analysis, coryza and myalgia were more frequent in Gamma variant cases; and hyposmia/anosmia, dysgeusia, and gastrointestinal tract symptoms in non-VoC cases. However, in the multivariate analysis after adjustment for multiple comparisons, hyposmia/anosmia (OR=0.304, adj p < 0.001) and dysgeusia (OR=0.385, adj p = 0.011) were the only symptoms significantly associated with the Gamma variant (Table 2 and Supplementary table 2) . We showed important differences in the clinical presentation between Gamma variant and non-VoC infection with a decreased frequency of hyposmia/anosmia and dysgeusia in Gamma variant cases. The increased occurrence of taste and smell disorders in COVID-19 has been considered a useful tool for the clinical triage of respiratory infections during the pandemic, with a frequency varying from 5% to 87% in COVID-19. 5-7 Thus, COVID-19 caused by the Gamma variant may present more often with cold-like symptoms. It has also been described that hyposmia/anosmia and dysgeusia are more common among younger and female patients. 6,8 However, there was no association between these symptoms and age or sex in our study. The increase in the proportion of COVID-19 cases caused by the Gamma variant in early 2021 was temporally associated with the beginning of the vaccination campaign in Brazil. 2 This context raised the concern that Gamma variant could evade previous SARS-CoV-2 immune response, as suggested in a previous in vitro study. 9 Our results do not corroborate this hypothesis since we found no association between immunization status or previous COVID-19 diagnosis, and Gamma variant infection. However, our study does not have enough power to analyze this association due to restricted circulation of Gamma variant soon after the vaccination campaign. The rise in Gamma variant cases in Brazil was also coincident with an increased COVID-19 incidence in younger patients. 10 Nonetheless, there was no association between age and Gamma variant infection in our study. This difference is probably explained by the COVID-19 vaccination rollout in Brazil, which prioritized elderly and HCW regardless of age. Our study has limitations. Our results might not be generalizable to severe cases of COVID-19 since our cohort comprised mainly mild cases. The temporal association between the vaccination campaign and the rise in Gamma variant cases might have impaired the evaluation of the association between vaccination status and the occurrence of Gamma variant infection by unadjusted or residual confounders. In conclusion, COVID-19 caused by the Gamma variant presents with different symptoms compared to non-VoC infection. The increase in Gamma variant cases should raise the awareness that COVID-19 may present more often with cold-like symptoms because of a decrease in the frequency of hyposmia/anosmia and dysgeusia. None. European Patients With Mild to Moderate COVID-19 Prevalence and Duration of Acute Loss of Smell or Taste in COVID-19 Patients 1 by antibodies elicited through natural SARS-CoV-2 infection or vaccination with an inactivated SARS-CoV-2 vaccine: an immunological study Boletim Observatório COVID-19 -Fiocruz, Brasil. Pages 7-9 We thank all the physicians of the HCW Health Services for helping with the collection of the clinical data and the LIM-46 team of the Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, Brazil, for performing the SARS-CoV-2 whole genome sequencing. This study was supported by the Itau Unibanco "Todos pela saúde" program.