Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in inadvertently vaccinated healthy children.

Twenty-seven children aged seven months to 5 years were inadvertently vaccinated with a COVID-19 vaccine, the CoronaVac (Sinovac, China), an inactivated SARS-CoV-2 vaccine, in two different cities of Sao Paulo State, Brazil. After the event, these children were monitored by local pediatricians and serum samples were collected at the first visit and 30 days after vaccination and tested for SARS-CoV-2 S1 serology with Ortho total IgG anti-S1 protein and Cpass, an ACE2 receptor binding domain inhibition assay. Only one child had a mild symptom after vaccination, with no other adverse events documented up to the 30 days follow-up. Of 27 children tested 3-9 days after vaccination, 5 (19%) had positive serology suggesting a previous natural SARS-CoV-2 infection, with all 19 tested on day 30 after vaccination and presenting with positive tests, with an increment of antibody titers in those initially positive. A low Cpass binding inhibition was observed in the first collection in 11 seronegative cases, with high titers among those anti-S1 positive. All children showed an important increase in antibody titers on day 30. The event allowed the documentation of a robust serological response to one dose of CoronaVac in this small population of young children, with no major adverse effects. Although it was an unfortunate accident, this event may contribute with future vaccine strategies in this age group. The data suggest that CoronaVac is safe and immunogenic for children.

Single-dose varicella vaccine effectiveness in Brazil: A case-control study.

BACKGROUND: Varicella vaccine was introduced into the Brazilian Immunization Program in October 2013, as a single-dose schedule administered at 15 months of age. Its effectiveness had not yet been assessed in the country. METHODS: A matched case-control study was carried out in São Paulo and Goiânia (Southeast and Midwest regions, respectively), Brazil. Suspected cases, were identified through a prospective surveillance established in the study sites. All cases had specimens from skin lesion collected for molecular laboratory testing. Cases were confirmed by either clinical or PCR of skin lesions and classified as mild, moderate, and severe disease. Two neighborhood controls were selected for each case. Cases and controls were aged 15-32 months and interviewed at home. Evidence of prior vaccination was obtained from vaccination cards. Univariate and multivariate logistic regression models were used, and odds ratio and its respective 95% confidence intervals were estimated. Vaccine effectiveness was estimated by comparing de odds of having received varicella vaccine among cases and controls. RESULTS: A total of 168 cases and 301 controls were enrolled. Moderate and severe illness, was found in 33.3% and 9.9% of the cases. Effectiveness of a single dose varicella vaccine was 86% (95%CI 72-92%) against disease of any severity and 93% (95%CI 82-97%) against moderate and severe disease. Out of 168 cases, 81.8% had positive PCR results for wild-type strains, and 22.0% were breakthrough varicella cases. Breakthrough cases were milder compared to non-breakthrough cases (p < .001). CONCLUSIONS: Effectiveness of single dose varicella vaccine in Brazil is comparable to that in other countries where breakthrough varicella cases have also been found to occur. The goal of the varicella vaccination program, along with disease burden and affordability should be taken into consideration when considering the adoption of a second dose of varicella vaccine into national immunization programs.

[Evaluation of the cold chain for vaccine conservation in primary healthcare centers in the South and Midwest regions of São Paulo city, Brazil, in 2011-2012]. / Avaliação da rede de frio para conservação de vacinas em unidades básicas de saúde das regiões Sul e Centro-Oeste do município de São Paulo em 2011-2012.

OBJECTIVE: to assess the cold chain capacity, health workers' immunobiological product conservation knowledge and practices in Primary Healthcare Centers (PHC) in São Paulo city, Brazil. METHODS: this descriptive study included 24 randomly selected PHC in the South and Midwest regions of the city; between December 2011 and July 2012, we interviewed the health workers on their vaccine conservation knowledge/practice and observed the local infrastructure, using a form developed for this project; we assigned points to items of the form and classified each PHC as sufficient, regular or insufficient. RESULTS: most of the 24 PHC evaluated were administered by Social Organizations; all of them had vaccine storage chambers; 5 PHC reported using their maximum storage capacity; 9 PHC were classified as having sufficient knowledge/practice and 15 as having regular knowledge/practice. CONCLUSION: in these PHC, cold chain utilization was close to its maximum capacity; many health workers did not have basic knowledge about vaccine conservation.

Avaliação da rede de frio para conservação de vacinas em unidades básicas de saúde das regiões Sul e Centro-Oeste do município de São Paulo em 2011-2012 / Evaluation of the cold chain for vaccine conservation in primary healthcare centers in the South and Midwest regions of São Paulo city, Brazil, in 2011-2012 / Evaluación de la cadena de frío para la conservación de vacunas en Unidades Básicas de Salud de las regiones Sur y Medio-Oeste de São Paulo en 2011-2012

OBJETIVO: avaliar capacidade da rede de frio (RF), conhecimento dos profissionais e práticas de conservação de imunobiológicos em unidades básicas de saúde (UBS) do município de São Paulo. MÉTODOS: estudo descritivo envolvendo amostra randômica de 24 UBS das regiões Sul e Centro-Oeste do município; de dezembro de 2011 a julho de 2012, foram entrevistados profissionais quanto ao conhecimento/prática em conservação de vacinas e observou-se a infraestrutura local, utilizando-se formulário desenvolvido para o projeto, sobre cujos itens atribuíram-se pontos e classificou-se cada UBS - suficiente, regular e insuficiente. RESULTADOS: a maioria das 24 UBS avaliadas era administrada por organizações sociais; todas possuíam câmaras de vacinas, cinco referiram utilizar sua capacidade máxima de armazenamento, nove UBS foram classificadas como de conhecimento/prática suficiente e 15 como de conhecimento/prática regular. CONCLUSÃO: a utilização da RF nessas UBS estava próxima da capacidade máxima; muitos profissionais não tinham conhecimentos básicos sobre conservação de vacinas.

OBJECTIVE: to assess the cold chain capacity, health workers' immunobiological product conservation knowledge and practices in Primary Healthcare Centers (PHC) in São Paulo city, Brazil. METHODS: this descriptive study included 24 randomly selected PHC in the South and Midwest regions of the city; between December 2011 and July 2012, we interviewed the health workers on their vaccine conservation knowledge/practice and observed the local infrastructure, using a form developed for this project; we assigned points to items of the form and classified each PHC as sufficient, regular or insufficient. RESULTS: most of the 24 PHC evaluated were administered by Social Organizations; all of them had vaccine storage chambers; 5 PHC reported using their maximum storage capacity; 9 PHC were classified as having sufficient knowledge/practice and 15 as having regular knowledge/practice. CONCLUSION: in these PHC, cold chain utilization was close to its maximum capacity; many health workers did not have basic knowledge about vaccine conservation.

OBJETIVO: evaluar la cadena de frío (CF), el conocimiento de los profesionales y las prácticas de conservación de vacunas en unidades básicas de salud (UBS) de São Paulo-SP, Brasil. MÉTODOS: estudio descriptivo de una muestra aleatoria de 24 UBS en las regiones Sur y Centro-Oeste del municipio; de diciembre del 2011 a julio del 2012, fueron entrevistados profesionales con respecto a sus conocimientos y prácticas en la conservación de vacunas, concomitantementese observó la infraestructura, utilizando un formulario desarrollado para el proyecto; atribuyéndose un puntaje específico para cada ítem, clasificamos las UBS como suficientes, regulares o insuficientes. RESULTADOS: la mayoría de las 24 UBS eran administradas por organizaciones sociales; todos tenían cámaras de vacunas; cinco informaron usar su capacidad máxima de almacenamiento; 9 UBS fueron clasificadas como suficientes y 15 como regulares. CONCLUSIÓN: la utilización de la CF en estas UBS estaba próxima al máximo; muchos profesionales no tenían conocimientos básicos acerca de conservación de vacunas.