is there 0 risk of hep b in 99.5 percent of childbirths

The claim that there is zero risk of hepatitis B (HBV) transmission in 99.5% of childbirths is not supported by the evidence. Multiple authoritative sources indicate that if a mother is infected with hepatitis B, the risk of transmitting the virus to her newborn without any preventive treatment is very high, around 90%. This perinatal transmission often leads to chronic infection in infants.

However, when appropriate interventions are applied immediately after birth, including administration of the hepatitis B vaccine and hepatitis B immune globulin (HBIG), the risk of transmission can be drastically reduced, often cited as reducing transmission rates to below 5-10%. This means that while the risk is greatly lowered, it is not completely eliminated or zero in nearly all cases. The World Health Organization and other medical guidelines emphasize the importance of screening pregnant women for HBV and providing newborns with timely prophylaxis to prevent vertical transmission.

Therefore, the statement that 99.5% of childbirths carry zero risk is misleading because it ignores the necessity and impact of medical intervention and does not reflect the baseline risk without treatment.