October 13, 2015
2 min read

CDC recommends shorter infant postvaccination testing interval for HBV

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Experts from the Centers for Disease Control and prevention are recommending the interval of postvaccination serologic testing for hepatitis B virus infection be shortened to age 9 to 12 months from 9 to 18 months, according to a data published in Morbidity and Mortality Weekly Report.

“This recommendation was prompted by the discontinuation of production of Comvax [Hib/HepB vaccine, Merck] and new data from the Enhanced Perinatal Hepatitis B Prevention Program supporting [postvaccinations serologic testing] 1 to 2 months after receipt of the last HepB vaccine dose, [at an age of at least] 9 months,” the researchers wrote in the report.

Sara Schillie, MD

Sarah Schillie

Researchers from the CDC, including Sarah Schillie, MD, reviewed the shortened interval of 9 to 12 months with health care professionals by evaluating new and existing study data on antibody to hepatitis B surface antigen (HBsAg; anti-HBs) levels among infants born to HBsAg-positive mothers.

In the Enhanced Surveillance: Perinatal Hepatitis B Program in Dallas County, Texas, among 348 infants born to mothers positive for HBsAg, postvaccination serologic testing (PVST) performed between 4 and 7 months (OR = 1.8; 95% CI, 1.2-2.8) and 8 and 11 months after the final vaccine dose (OR = 4.4; 95% CI, 1.3-14.5) was associated with lower anti-HBs levels compared with PVST 1 to 3 months after vaccination, according to the report.

In another study, CDC experts evaluated study data of 8,105 infants without HBsAg enrolled in the Enhanced Perinatal Hepatitis B Prevention Program, who were born to mothers positive for HBsAg. The infants’ anti-HBs levels were measured in intervals from 1 to 16 months after the final HepB vaccine dose. The report stated that the percentage of infants whose anti-HBs levels were less than 10 mIU/mL were: 2% at 1 to 2 months; 2.8% at 3 to 4 months; 5.1% at 5 to 6 months; 7.8% at 7 to 8 months; 9.3% at 9 to 10 months; 13.3% at 11 to 12 months; 16.3% at 13 to 14 months; and 21.6% at 15 to 16 months (P < .01 for all). Nearly 22.3% of all infants in this study underwent PVST more than 6 months after the final vaccine dose, according to the research.

“The optimal timing for PVST to detect a vaccine response generally is 1 [to] 2 months after the final dose of the HepB vaccine series,” the researchers wrote. “Results of tests for HBsAg can be transiently positive for 1 [to] 18 days after vaccination. PVST should be performed no earlier than age 9 months to avoid detection of passive anti-HBs from hepatitis B immune globulin administered at birth and to maximize the likelihood of detecting late HBV infection.”

A benefit of PVST between 9 and 12 months is that it provides an opportunity for the child to undergo HBV testing twice at regular wellness visits: one at the 9-month visit and one at the 12-month visit, according to researchers. Another “added benefit” to the shortened interval to PVST is a shorter time period in which nonresponders are at risk for transmission after close contact with HBV.

“Earlier PVST enables prompt revaccination of those infants needing revaccination with a second 3-dose HepB vaccine series to attain protective anti-HBs levels,” the researchers wrote. “A shortened interval might also increase adherence with recommendations for timely completion of PVST and conserve public health resources involved in providing case management services.”

The researchers concluded: “Although no data are available, CDC subject matter experts postulate that harm will not occur as a result of a shortened PVST interval. PVST (consisting of HBsAg and anti-HBs) for infants born to HBsAg-positive mothers should be performed at age 9 [to] 12 months, or 1 [to] 2 months after the final dose of the HepB vaccine series if completion of the series is delayed.”

Disclosures: Schillie reports no relevant financial disclosures.