Individuals who were mildly symptomatic following infection with SARS-CoV-2 B.1.1.28 have neutralizing antibodies to the P.1 variant.

ObjectivesTo evaluate if antibodies induced by infection with a different SARS-CoV-2 virus strain neutralize the P.1 variant. MethodsConvalescent sera from 60 individuals following a documented SARS-CoV-2 infection were assayed for neutralizing antibody titer against both strains. ResultsFifty-six and 50 sera were positive for neutralizing antibodies against the ancestral and P.1 strains, respectively. Neutralization titers were higher against the ancestral strain, but in the majority of patients differences did not differ by more than a single dilution. ConclusionsNeutralizing antibodies that were generated following infection with SARS-CoV-2 B.1.1.28 were effective in vitro, against the SARS-CoV-2 P.1. variant.

Performance of At-Home Self-Collected Saliva and Nasal-Oropharyngeal Swabs in the Surveillance of COVID-19

SARS-CoV-2 quickly spread in the worldwide population by contact with oral and respiratory secretions of infected individuals, imposing social restrictions to control the infection. Massive testing is essential to breaking the chain of COVID-19 transmission. The aim of this study was to compare the performance of at-home self-collected samples - saliva and combined nasal-oropharyngeal swabs (NOP) - for SARS-CoV-2 detection in a telemedicine platform for COVID-19 surveillance. We analyzed 201 patients who met the criteria of suspected COVID-19. NOP sampling were combined (nostrils and oropharynx) and saliva collected using a cotton pad device. Detection of SARS-COV-2 was performed by using the Altona RealStar(R) SARS-CoV-2 RT-PCR Kit 1.0. According to our data, there was an overall significant agreement ({kappa} coefficient value of 0.58) between the performances of saliva and NOP. Assuming that positive results in either sample represent true infections, 70 patients positive for SARS-CoV-2 were identified, with 52/70 being positive in NOP and 55/70 in saliva. This corresponds to sensitivities of 74.2% (95% CI; 63.7% to 83.1%) for NOP and 78.6% (95% CI; 67.6% to 86.6%) for saliva. We also found a strong correlation ({beta}-coefficients < 1) between the cycle threshold values in saliva and NOP. Ageusia was the only symptom associated with patients SARS-CoV-2 positive only in NOP (p=0.028). In conclusion, our data show the feasibility of using at-home self-collected samples (especially saliva), as an adequate alternative for SARS-CoV-2 detection. This new approach of testing can be useful to develop strategies for COVID-19 surveillance and for guiding public health decisions.