India, June 22 -- I am expecting a baby. I have read that the Hepatitis B vaccine should be given. Why does my baby need this vaccine? What does it protect against and is it really necessary? It is completely natural for parents to wonder why a newborn needs a vaccine so soon after birth. However, when it comes to Hepatitis B, early protection is not only important but can be life-saving. Hepatitis B is a viral infection that affects the liver and remains a significant public health concern. Globally, an estimated 5.6 million children under five years of age are living with Hepatitis B infection (1). According to estimates from the WHO and CDC, the prevalence of chronic Hepatitis B infection among children under five years of age has fallen to below 1% globally, compared with approximately 5% before the widespread introduction of Hepatitis B vaccination (2). Although older children and adults may develop symptoms such as jaundice, fatigue or abdominal pain, many infected infants have no symptoms at all. The real concern lies in what happens silently over time. When Hepatitis B infection is acquired during infancy, the risk of developing chronic infection is as high as 90%. Among children infected between one and five years of age, the risk remains substantial at around 30% (2). Chronic Hepatitis B infection can later lead to serious complications such as liver cirrhosis, liver failure and even liver cancer during adolescence or adulthood. One of the most important reasons for vaccinating newborns is that Hepatitis B can be transmitted from an infected mother to her baby during childbirth, also known as vertical transmission. In fact, mother-to-child transmission remains one of the commonest routes through which Hepatitis B infection is acquired worldwide. Babies can also become infected through exposure to infected blood or body fluids later in life, but preventing infection at birth is particularly important because infection acquired during this period carries the highest risk of becoming lifelong disease. Certain groups of children are also at increased risk of acquiring Hepatitis B infection later in childhood. These include children who require repeated blood transfusions, such as those with thalassemia, sickle cell disease or other chronic blood disorders, children undergoing dialysis, and those who may require frequent medical procedures involving blood products. Although modern blood screening practices have made transfusions remarkably safe, vaccination provides an additional and highly effective layer of protection. The Hepatitis B vaccine provides highly effective protection against this infection and works best when the first dose is administered as early as possible after birth. For this reason, all newborns are recommended to receive a birth dose of Hepatitis B vaccine within 24 hours of delivery. This early dose serves as the first and most critical step in preventing mother-to-child transmission. If a mother is known to be infected with Hepatitis B, the newborn receives both the vaccine and Hepatitis B immunoglobulin (HBIG) within 12 hours of birth, providing an additional layer of protection. When administered on time and followed by completion of the full vaccination schedule, more than 95% of infections can be prevented. (2) In India, Hepatitis B vaccination forms part of the routine childhood immunisation programme. After the birth dose, additional doses are administered at 6, 10 and 14 weeks of age. Completing all recommended doses is essential to ensure long-lasting immunity and optimal protection against infection. Hepatitis B vaccine has an excellent safety record and has been used in millions of children worldwide for several decades. Side effects, if they occur, are generally mild and may include temporary soreness at the injection site, mild fever or irritability. Serious adverse effects are extremely rare. Children who have missed infant vaccination can still receive catch-up Hepatitis B vaccination later in childhood and adolescence. Your paediatrician can advise the appropriate schedule based on the child's age and previous vaccination status. Parents should remember that Hepatitis B is a preventable infection that can have serious long-term consequences when acquired early in life. A timely birth dose, followed by completion of the routine vaccination schedule, provides highly effective protection against chronic infection and liver disease. 1. Polaris Observatory Collaborators. Global prevalence, cascade of care, and prophylaxis coverage of hepatitis B in 2022: a modelling study. Lancet Reg Health Southeast Asia. 2023 2. Centers for Disease Control and Prevention. Clinical overview of hepatitis B. Atlanta: CDC; 2025 Dr Anupam Sibal is a leading Pediatric Gastroenterologist and Hepatologist with over three decades of experience, and five books to his credit, including the national best seller Is Your Child Ready to face the World?...