What clinical intervention should be performed if an infant is delivered from a mother with positive HBsAg?

The appropriate clinical intervention for an infant delivered from a mother with a positive HBsAg (hepatitis B surface antigen) is to administer hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth. This immediate action is crucial in preventing the transmission of hepatitis B from the infected mother to her newborn.

The hepatitis B vaccine works by stimulating the infant's immune system to produce antibodies against the hepatitis B virus, while HBIG provides immediate passive immunity by supplying pre-formed antibodies. Administering both components together is highly effective in reducing the risk of hepatitis B infection in the neonate to nearly 90%.

Other options do not address the critical need for immediate prophylaxis against hepatitis B. Isolation of the infant does not prevent transmission, as the virus is not spread through casual contact; rather, it's transmitted through blood and bodily fluids. Placing the infant on a low-fat diet is not relevant in this context since diet does not influence hepatitis B prevention. Moreover, stopping breastfeeding is not necessary or recommended, as transmission through breast milk is considered to be low risk if the infant has received the appropriate prophylaxis.

Thus, administering the hepatitis B vaccine and immune globulin is the most effective and recommended strategy for protecting