HBV vaccine is recommended for routine immunization of all infants beginning at birth and for all children and adolescents through 18 years of age who have not been immunized previously (see Fig. 94-1). It also is recommended as a preexposure vaccination for older children and adults at increased risk of exposure to HBV, including persons undergoing hemodialysis, recipients of clotting factor concentrates, residents and staff of institutions for developmentally disabled persons, men who have sex with men, injectable drug users, inmates of juvenile detention and other correctional facilities, and health care workers. HBV vaccine already has shown effectiveness in reducing the incidence of hepatocellular carcinoma in high-risk populations. Routine prenatal screening for HBsAg is recommended for all pregnant women in the United States. Infants born to HBsAg-positive mothers should receive HBV vaccine and hepatitis B immunoglobulin (HBIG) (0.5 mL) within 12 hours of birth, with subsequent vaccine doses at 1 month and 6 months of age followed by testing for HBsAg and anti-HBs at 9 to 15 months of age. Infants born to mothers whose HBsAg status is unknown should receive vaccine within 12 hours of birth. If maternal testing is positive for HBsAg, the infant should receive HBIG as soon as possible (no later than 1 week of age). The combination of HBIG and vaccination is 99% effective in preventing vertical transmission of HBV. Vaccination alone without HBIG may prevent 75% of cases of perinatal HBV transmission and approximately 95% of cases of symptomatic childhood HBV infection.
Postexposure prophylaxis of unvaccinated persons usingHBIG and vaccine is recommended following needle stick injuries with blood from an HBsAg-positive patient and forhousehold members with intimate contact, including sex partners.
Urinary tract infections (UTIs) include cystitis (infection localized to the bladder), pyelonephritis (infection of the renal parenchyma, calyces, and renal pelvis), and renal abscess, which may be intrarenal or perinephric. The urinary tract and urine are normally sterile. Escherichia coli, ascending from bowel flora, accounts for 90% of first infections and 75% of recurrent infections. Over 90% of nephritogenic E. coli possess P fimbriae that binds to uroepithelial cells and P blood group antigens. Individuals with high-level expression of P1 blood group antigen are predisposed to pyelonephritis and bacteremia, as well as recurrent UTIs. Other bacteria commonly causing infection include Klebsiella, Proteus, Enterococcus, and Pseudomonas. Staphylococcus saprophyticus is associated with UTI in some children and in sexually active adolescent girls. S. saprophyticus, Chlamydia trachomatis, and E. coli are the chief causes of the acute urethral syndrome, or postcoital urethritis, which typically occur 12 to 72 hours after sexual intercourse.
Approximately 8% of girls and 2% of boys have a UTI by 11 years of age. The lifetime incidence of UTI in females is about 30% compared to only 1% in males. Approximately 75% of infants younger than 3 months of age with bacteriuria are male compared with only 10% between 3 and 8 months of age. After 12 months of age, UTI in healthy children usually is seen in girls.