REFILE-Early childhood hep B vaccine gives long-term protection

Last Updated: 2014-07-24

(Adds "pertussis" in parenthetical phrase in para 3, and in para 11, replaces the word "randomized" with "reassigned")

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Immunity to hepatitis B after primary immunization in early childhood gives long-term protection, a new study suggests.

In children primed at 3, 5 and 11 months of age, immunization with conjugate or monovalent vaccines induced long-lasting immune memory against HBV, and was well tolerated, the researchers report online June 22 in Vaccine.

Antibody persistence and immune memory were similar, suggesting that the protection given by the combined DTPa-HBV-IPV/Hib vaccine (hexavalent diphtheria-tetanus-pertussis- hepatitis B-inactivated poliomyelitis - Haemophilus influenzae type b) and monovalent HBV vaccines is likely to last as long, they write.

"These findings surprised us positively and confirmed that hepatitis B vaccines are very well tolerated by children. We found that it is not the necessary to change our immunization schedule regarding the administration of the HBV component of the combined vaccine," wrote Dr. Maria Avdicova, of the Regional Authority of Public Health in Banska Bystrica, Slovakia, by email to Reuters Health.

"Vaccination against HBV is an example of a very positive story in many countries, including my own," although the schedule may vary by country, she wrote.

Dr. Walter Orenstein, of the Emory University School of Medicine and the Emory Vaccine Center, wrote in an email, "The study shows that immunity to hepatitis B following a primary series in early childhood is long term and the data do not support a need for boosters with increasing time since vaccination. A primary series alone appears adequate to induce long-term immunity."

Doctors should keep doing what they've been doing, he said.

To assess the long-term HBV antibody persistence 10 to 11 years after primary vaccination in infancy, Dr. Avdicova and colleagues looked at a vaccination trial conducted between 1998 and 1999.

All 312 children who took part in the earlier study were invited to participate in the new phase 4 open, follow-up challenge trial in 2010, at 12 centers in Slovakia.

Children were ineligible if they had received HBV vaccination since completing the initial vaccination; if they had a history of HBV infection; if they had received immunoglobulin or blood products within the previous three months or planned to receive them during the study; if they were immunosuppressed; or if they had received or planned to receive any other vaccine within 30 days before or after the HBV dose.

In the earlier trial, the children had received three doses of either DTPa-HBV-IPV/Hib, or DTPa-IPV/Hib + HBV, at 3, 5, and 11 months of age, and in this new study they were reassigned to their original group. All 185 participants received one challenge dose intramuscularly in the non-dominant deltoid. Blood samples were collected before the challenge dose and one month after.

Overall, 48.4% in the DTPa-HBV-IPV/Hib group and 58.4% in the DTPa-IPV/Hib + HBV group showed persisting anti-HBs antibody concentrations 10 mIU/ml.

After the HBV challenge dose, the children with anti-HBs 100 mIU/ml increased from 14.7% to 93.6% in the DTPa-HBV-IPV/Hib group and from 19.1% to 94.4% in the DTPa-IPV/Hib + HBV group.

In both groups, antibody against hepatitis B surface antigen (anti-HBs) geometric mean antibody concentration (GMC) increased at least 187-fold. An anamnestic response (4-fold increase in initially seropositive subjects, or anti-HBs concentration 10 mIU/ml in initially seronegative subjects) was seen in 96.8% and 96.6% of children in the DTPa-HBV-IPV/Hib and DTPa-IPV/Hib + HBV groups, respectively.

There were no serious adverse events related to the challenge vaccination, the authors said.

"These findings reinforce the use of a 3, 5, and 12 month schedule used by a number of countries," wrote Dr. Orenstein, who was not involved in the study.

"Hepatitis B vaccine is important to provide to all infants. In the US, the primary schedule consists of three doses, administered at birth, 1 to 2 months of age, and 6 to 18 months of age," he wrote.

"The vaccine not only prevents clinical hepatitis and the liver damage that results from acute infection but also prevents hepatitis B induced liver cancer. In fact, hepatitis B vaccine is our first anti-cancer vaccine, with human papilloma virus (HPV) our second anti-cancer vaccine," he wrote.

In a separate study reported online July 2 in Vaccine, Dr. Carol Yuet Sheung Yuen and colleagues at the Li Ka Shing Faculty of Medicine of the University of Hong Kong in Pokfulam, conducted a detailed literature search of articles related to the uptake of influenza vaccination during pregnancy, and found it suboptimal, ranging from 1.7% to 88.4% for seasonal influenza, and from 6.2% to 85.7% for A/H1N1 pandemic influenza.

Many pregnant women were unaware that they were at high risk for influenza and its complications during pregnancy, underestimated the threat of influenza to themselves and their fetus, and were concerned about the safety and efficacy of having the influenza vaccine during pregnancy.

Negative media reports contributed to the perception that influenza vaccination during pregnancy was risky and most health care providers did not recommend the vaccine to their pregnant clients.

The authors advise health care providers to recommend the vaccines and provide access to them.

SOURCES: http://bit.ly/1l3FKFB and http://bit.ly/1yryuf4

Vaccine 2014.