The need for fast-track, high-quality and low-cost studies about the role of the BCG vaccine in the fight against COVID-19.

Bacillus Calmette-Guérin (BCG) vaccination is routine and near-universal in many low- and middle-income countries (LMIC). It has been suggested that BCG can have a protective effect on COVID-19 morbidity and mortality. This commentary discusses the limitations of the evidence around BCG and COVID-19. We argue that higher-quality evidence is necessary to understand the protective effect of the BCG vaccine from existing, secondary data, while we await results from clinical trials currently conducted in different settings

Previous BCG vaccination is associated with less severe clinical progression of COVID-19

Background: BCG vaccination, originally used to prevent tuberculosis, is known to “train” the immune system to improve defence against viral respiratory infections. We investigated whether a previous BCG vaccination is associated with less severe clinical progression of COVID-19./ Methods: A case-control study comparing the proportion with a BCG vaccine scar (indicating previous vaccination) in cases and controls presenting with COVID-19 to health units in Brazil. Cases were subjects with severe COVID-19 (O2 saturation < 90%, severe respiratory effort, severe pneumonia, severe acute respiratory syndrome, sepsis, and septic shock). Controls had COVID-19 not meeting the definition of “severe” above. Unconditional regression was used to estimate vaccine protection against clinical progression to severe disease, with strict control for age, comorbidity, sex, educational level, race/colour, and municipality. Internal matching and conditional regression were used for sensitivity analysis./ Results: BCG was associated with high protection against COVID-19 clinical progression, over 87% (95% CI 74–93%) in subjects aged 60 or less and 35% (95% CI − 44–71%) in older subjects./ Conclusions: This protection may be relevant for public health in settings where COVID-19 vaccine coverage is still low and may have implications for research to identify vaccine candidates for COVID-19 that are broadly protective against mortality from future variants. Further research into the immunomodulatory effects of BCG may inform COVID-19 therapeutic research.

Previous BCG vaccination is associated with less severe clinical progression of COVID-19

BACKGROUND: BCG vaccination, originally used to prevent tuberculosis, is known to "train" the immune system to improve defence against viral respiratory infections. We investigated whether a previous BCG vaccination is associated with less severe clinical progression of COVID-19 METHODS: A case-control study comparing the proportion with a BCG vaccine scar (indicating previous vaccination) in cases and controls presenting with COVID-19 to health units in Brazil. Cases were subjects with severe COVID-19 (O2 saturation < 90%, severe respiratory effort, severe pneumonia, severe acute respiratory syndrome, sepsis, and septic shock). Controls had COVID-19 not meeting the definition of "severe" above. Unconditional regression was used to estimate vaccine protection against clinical progression to severe disease, with strict control for age, comorbidity, sex, educational level, race/colour, and municipality. Internal matching and conditional regression were used for sensitivity analysis. RESULTS: BCG was associated with high protection against COVID-19 clinical progression, over 87% (95% CI 74-93%) in subjects aged 60 or less and 35% (95% CI - 44-71%) in older subjects. CONCLUSIONS: This protection may be relevant for public health in settings where COVID-19 vaccine coverage is still low and may have implications for research to identify vaccine candidates for COVID-19 that are broadly protective against mortality from future variants. Further research into the immunomodulatory effects of BCG may inform COVID-19 therapeutic research

Assessing risk behaviors and prevalence of sexually transmitted and blood-borne infections among female crack cocaine users in salvador - Bahia, Brazil

Crack cocaine use is associated with risky sexual behaviors and sexually transmitted infections (STIs), including HIV. We investigated sociodemographic and behavioral characteristics and infection rates in female crack cocaine users from impoverished communities of Salvador, Bahia, Brazil. A sample of 125 female crack cocaine users was recruited. Overall, the interviewees had low educational level and high rate of unemployment (close to 90%). One-third (37%) reported having traded sex for money or drugs, and 58% reported that they had not used condoms during intercourse in the last 30 days. The prevalence of infections was low: HIV-1.6%; HCV-2.4%; HBV- 0.8%; HTLV I/II-4.0%; and syphilis-4.0%. The combination of dire poverty and high prevalence of risk behaviors turn such populations a preferential target of initiatives aiming to reduce drug-related harm and promote social development. Low infection rates should not be viewed with complacency, but as a window of opportunity to implement prevention initiatives and reduce social marginalization

A case-control study of HTLV-infection among blood donors in Salvador, Bahia, Brazil - associated risk factors and trend towards declining prevalence Estudo da infecção do HTLV entre doadores de sangue de Salvador, Bahia, Brasil

Previous data suggest that Salvador, the capital of the State of Bahia, a northeastern state of Brazil, has the highest prevalence of HTLV infection in blood donors among Brazilian cities. The aim of this case-control study was to identify the determinants of risk for HTLV infection among blood donors in the city of Salvador. Between January 2000 and December 2003, 504 blood donors with positive screening tests for HTLV infection (unconfirmed prevalence of 0.48%) were invited to participate in our study. A total of 154 had performed a Western Blot (WB) test, 139 were of which found to be positive (false positive screening rate 9.9%). Using a standardized questionnaire, a single interviewer obtained information on demographic, socio-economical and educational characteristics, as well as sexual behavior from 91 out of the 139 positive by WB and from 194 HTLV-negative blood donors. Prevalence of HTLV infection was 0.48%. Multivariate analysis revealed women (OR 3.79 [1.61-8.88], p=0.002), low family income* (OR 3.37 [1.17-9.66], p=0.02), self-reported history of sexual transmitted diseases (OR 6.15 [2.04-18.51], p=0.001), 2 or more sexual partners during life (OR 9.29 [2.16-39.94], p=0.0020) and inconsistent use of condoms (OR 4.73 [1.98-11.26], p=0.0004) as risk factors for HTLV infection. In accordance with previous published data, our results point to an association between low socio-economical level, poor education and unsafe sexual behavior with HTLV infection. We observed a lower prevalence of HLTV infection when compared to previous data.Estudos anteriores sugerem que Salvador, capital da Bahia, um estado do Nordeste do Brasil, tem a maior prevalência de infecção por HTLV em doadores de sangue entre as cidades brasileiras. O objetivo deste estudo caso-controle foi identificar os determinantes de risco para a infecção por HTLV entre doadores de sangue em Salvador. Entre janeiro 2000 e dezembro 2003, 504 doadores de sangue positivos para a infecção por HTLV em teste de triagem (prevalência não confirmada de 0,48%) foram convidados para participar deste estudo. O Western Blot foi realizado em 154 destes doadores dos quais 139 foram confirmados como positivos (taxa de triagem falso positivo de 9,9%). A partir de um questionário padronizado, informações demográficas, socioeconômicas e sobre as características educacionais assim como sobre o comportamento sexual foram obtidas de 91 participantes, entre os 139 Western Blot positivos e de 194 participantes HTLV-negativos. A prevalência da infecção de HTLV foi de 0,48%. A análise multivariada revelou os seguintes fatores de risco para a infecção de HTLV: sexo feminino (OR 3.79 [1.61-8.88], p=0.002), baixa renda familiar (OR 3.37 [1.17-9.66], p=0.02), relato espontâneo de DST (OR 6.15 [2.04-18.51], p=0.001), dois ou mais parceiros sexuais durante a vida sexual, (OR 9.29 [2.16-39.94], p=0.0020), utilização inconstante de camisinhas (OR 4.73 [1.98-11.26], p=0.0004). Conforme dados da literatura, nossos resultados indicam uma associação entre o baixo nível socioeconômico, a baixa escolaridade e o comportamento sexual de risco com a infecção por HTLV