An Italian study on hepatitis B (HBV) vaccine coverage between 1993 and 2014 has shown that more work is needed to increase vaccination rates in Italy’s universal HBV vaccination program, according to data published in Clinical Infectious Diseases.

Maria Elena Tosti, Lead Researcher at the the Superiore di Sanità, Centro Nazionale di Epidemiologia, Sorveglianza e Promozione della Salute, Rome and colleagues analyzed data between 1993-2014 from the Italian Surveillance System for Acute Viral Hepatitis to examine people who had been successfully vaccinated against acute virus and the number of preventable cases if people who were not vaccinated were immunized. The study researchers also examined data on individuals who failed to be immunized.

Of 12,472 patients with HBV, 11,311 individuals had HBV vaccination data available for study. There were no significant increases in yearly percentage of infections in vaccinated individuals during the study period. The median age for acute HBV infection was 36 years and nearly 75% of cases were in men. Of these acute infections, 362 of the patients had received the vaccine, and immunization data were available for 277 of those cases, the researchers noted in the study. Fifty cases had the vaccine before exposure to the virus in the correct dosage and schedule.


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“The molecular characterization of the samples collected from 13 of the vaccinated individuals with breakthrough infection who were HBV-DNA positive showed that 7 of them were infected with HBV wild-type and 6 with S-gene mutants potentially able to evade the vaccine-induced immunity. Three of these cases developed acute hepatitis B despite the presence of protective levels of anti-HBs (≥ 10 mIU/mL),” the researchers wrote.

In the 10,949 unvaccinated  people who had HBV,  213 were missed by the mandatory vaccination program and 2821 unvaccinated people were at high risk of contracting the disease. The researchers noted that for people at high risk, the vaccine is “strongly recommended and free of charge.”  They reported that most of these high risk cases were among adolescents living in southern Italy (87.8%).

Risk factors most frequently associated with HBV were: living with a partner who was a carrier of the HBV surface antigen, homosexual or bisexual sex practices, and illegal drug use. Sixty-three percent of unvaccinated persons who lived with an HBV surface antigen carrier were unaware of the risk.

A lack of trust in vaccines, negative attitudes, and incorrect beliefs, in addition to little or no communication with providers and lack of understanding of HBV severity were cited as top reasons that people avoided getting the HBV vaccine, according to the paper.

“Further efforts to achieve and maintain a high level of public confidence in the safety and efficacy of hepatitis B vaccination are essential to reaching high coverage rates, especially among individuals at increased risk of HBV infection,” researchers concluded.

Reference

Tosti ME, Alfonsi V, Lacorte E et al. Acute hepatitis B after the implementation of universal vaccination in Italy: results from 22 years of surveillance (1993–2014). Clin Infect Dis. 2016; 62(11):1412–8