What is the relationship between Bacillus Calmette-Guérin (BCG) vaccine and Sudden Infant Death Syndrome (SIDS)?

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Last updated: April 27, 2025View editorial policy

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From the Guidelines

There is no established causal link between the BCG vaccine and Sudden Infant Death Syndrome (SIDS), and in fact, immunization may have a protective effect against SIDS, as suggested by a meta-analysis that found the risk of SIDS to be halved by immunization 1. The BCG vaccine, which protects against tuberculosis, has been used safely for decades in many countries without evidence suggesting it increases SIDS risk. Some research has suggested that BCG vaccination might have a protective effect against SIDS through its immune-modulating properties, though this remains an area of ongoing research 1. The vaccine is typically administered as a single dose shortly after birth in countries with high tuberculosis prevalence. Common side effects include a small sore at the injection site that may leave a small scar, mild fever, and occasionally swollen lymph nodes, but these are normal immune responses. Parents should be reassured that major health organizations worldwide continue to recommend BCG vaccination in appropriate settings based on tuberculosis risk, and the vaccine's safety profile is well-established 1. The causes of SIDS are multifactorial and likely involve a combination of environmental and biological factors, with the most established prevention strategy being placing infants on their backs to sleep. Key factors to reduce SIDS risk include:

  • Avoiding overheating and head covering in infants
  • Ensuring a safe sleep environment
  • Avoiding exposure to tobacco smoke and illicit drugs
  • Promoting breastfeeding
  • Following recommended immunization schedules, which may have a protective effect against SIDS 1.

From the Research

BCG Vaccine and Sudden Infant Death

  • There is no direct evidence in the provided studies that links the BCG vaccine to sudden infant death.
  • A study published in 2019 2 found that early BCG vaccination in healthy infants who are preterm and/or have low birth weights has a similar safety profile, reactogenicity, and TST conversion rate as delayed vaccination.
  • The World Health Organization's (WHO) position paper on BCG vaccine, published in 2018 3, provides recommendations on the use of BCG vaccine, but does not mention sudden infant death as a potential risk.
  • Other studies have investigated the safety and immunogenicity of BCG vaccine, including a systematic review of the safety of BCG revaccination 4, a comparison of intradermal and percutaneous routes of BCG administration 5, and a study on the immune responses induced by oral and intradermal BCG vaccination 6.
  • However, none of these studies provide evidence on the relationship between BCG vaccine and sudden infant death.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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