Abstract Brazil has a huge number of cases and deaths due to coronavirus disease 2019 (COVID-19); however, few studies have dealt with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among familial contacts in Brazil. Here, we report our findings on transmission in a family-based study in Bauru, São Paulo, Brazil. The study, conducted from July to November 2020, comprised 974 individuals with 233 index patients and 741 familial contacts. Familial contacts were evaluated using the rapid COVID-19 Ag ECO and reverse transcription-polymerase chain reaction (RT-PCR) tests immediately after the index patient diagnosis. The antigen-based rapid test was validated in 121 individuals using RT-PCR as the gold standard. Additionally, 30 days later, familial contacts were evaluated for IgM and IgG antibodies against SARS-CoV-2. We found 333 cases of COVID-19 among familial contacts (44.9%). A positive correlation was observed between the time elapsed from the onset of symptoms until the index patient’s COVID-19 testing and the number of family contacts infected by SARS-CoV-2. Early SARS-CoV-2 testing and familial contact evaluation are relevant strategies to contain transmission.

Resumo O Brasil apresenta um alto número de casos e óbitos por coronavírus (COVID-19), apesar disso, poucos estudos tratavam da infecção pelo coronavirus-2 causador de síndrome respiratória aguda grave (SARS-CoV-2) entre contatos familiares no Brasil. Relatamos aqui nossos achados sobre a transmissão de SARS-CoV-2 em um estudo de base familiar de Bauru, no estado de São Paulo, Brasil. O estudo foi realizado de julho a novembro de 2020 e compreendeu 974 indivíduos, sendo 233 pacientes índice e 741 contatos familiares. Os contatos familiares foram avaliados por meio do teste rápido COVID-19 Ag ECO Test e RT-PCR imediatamente após o diagnóstico do paciente índice. O uso do teste rápido baseado em antígeno foi validado em 121 indivíduos utilizando RT-PCR como padrão ouro. Adicionalmente, 30 dias após a avaliação inicial, os contatos familiares foram avaliados quanto à presença de anticorpos IgM e IgG contra SARS-CoV-2. Encontramos 333 casos de COVID-19 entre contatos familiares (44,9%). Observamos uma correlação positiva entre o tempo decorrido entre o início dos sintomas e o teste para COVID-19 do paciente índice e o número de contatos familiares infectados por SARS-CoV-2. A testagem precoce da infecção por SARS-CoV-2 e a avaliação de contatos familiares são estratégias relevantes para conter a transmissão.

Abstract Brazil has a huge number of cases and deaths due to coronavirus disease 2019 (COVID-19); however, few studies have dealt with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among familial contacts in Brazil. Here, we report our findings on transmission in a family-based study in Bauru, São Paulo, Brazil. The study, conducted from July to November 2020, comprised 974 individuals with 233 index patients and 741 familial contacts. Familial contacts were evaluated using the rapid COVID-19 Ag ECO and reverse transcription-polymerase chain reaction (RT-PCR) tests immediately after the index patient diagnosis. The antigen-based rapid test was validated in 121 individuals using RT-PCR as the gold standard. Additionally, 30 days later, familial contacts were evaluated for IgM and IgG antibodies against SARS-CoV-2. We found 333 cases of COVID-19 among familial contacts (44.9%). A positive correlation was observed between the time elapsed from the onset of symptoms until the index patient’s COVID-19 testing and the number of family contacts infected by SARS-CoV-2. Early SARS-CoV-2 testing and familial contact evaluation are relevant strategies to contain transmission.

Resumo O Brasil apresenta um alto número de casos e óbitos por coronavírus (COVID-19), apesar disso, poucos estudos tratavam da infecção pelo coronavirus-2 causador de síndrome respiratória aguda grave (SARS-CoV-2) entre contatos familiares no Brasil. Relatamos aqui nossos achados sobre a transmissão de SARS-CoV-2 em um estudo de base familiar de Bauru, no estado de São Paulo, Brasil. O estudo foi realizado de julho a novembro de 2020 e compreendeu 974 indivíduos, sendo 233 pacientes índice e 741 contatos familiares. Os contatos familiares foram avaliados por meio do teste rápido COVID-19 Ag ECO Test e RT-PCR imediatamente após o diagnóstico do paciente índice. O uso do teste rápido baseado em antígeno foi validado em 121 indivíduos utilizando RT-PCR como padrão ouro. Adicionalmente, 30 dias após a avaliação inicial, os contatos familiares foram avaliados quanto à presença de anticorpos IgM e IgG contra SARS-CoV-2. Encontramos 333 casos de COVID-19 entre contatos familiares (44,9%). Observamos uma correlação positiva entre o tempo decorrido entre o início dos sintomas e o teste para COVID-19 do paciente índice e o número de contatos familiares infectados por SARS-CoV-2. A testagem precoce da infecção por SARS-CoV-2 e a avaliação de contatos familiares são estratégias relevantes para conter a transmissão.

Background: HLA allele identification is used in bone marrow transplant programs as HLA compatibility between the donor and recipient may prevent graft rejection. Objective: This study aimed to estimate the frequency of alleles and haplotypes of the HLA system in the region of Bauru and compare these with the frequencies found in other regions of the country. Methods: HLA-A*, HLA-B*, and HLA-DRB1* allele frequencies and haplotypes were analyzed in a sample of 3542 volunteer donors at the National Registry of Voluntary Bone Marrow Donors (REDOME) in Bauru. HLA low resolution typing was performed using reverse line blot with the Dynal Reli(tm) SSO-HLA Typing Kit and automated Dynal AutoReli(tm)48 device (Invitrogen, USA). Results: Twenty, 36, and 13 HLA-A*, HLA-B*, and HLA-DRB1* allele groups, respectively, were identified. The most common alleles for each locus were HLA-A*02, HLA-B*35, and HLA-DRB1*07. The most frequent haplotype was A*01-B*08-DRB1*03. Allele and haplotype frequencies were compared to other regions in Brazil and the similarities and differences among populations are shown. Conclusion: The knowledge of the immunogenic profile of a population contributes to the comprehension of the historical and anthropological aspects of different regions. Moreover, this helps to find suitable donors quickly, thereby shortening waiting lists for transplants and thus increasing survival rates among recipients.