CROI 2022: Immunoglobulin-free strategy prevents mother-to-child HBV transmission

Pregnant women with hepatitis B virus who received tenofovir disoproxil fumarate at least 4 weeks prior to delivery were less likely to transmit the virus to their infants, even those who did not receive immunoglobulin, data show.

“Many low- and middle-income countries face difficulty in accessing immunoglobulin and HBV DNA quantification,” Olivier Segeral, of the University of Health Sciences in Phnom Penh, Cambodia, said during a virtual abstract presentation at the Conference on Retroviruses and Opportunistic Infections. “The objective of the TA-PROHM study was to evaluate the effectiveness of an immunoglobulin-free strategy to prevent HBV mother-to-child transmission.”

According to Segeral, the novel strategy involved:

• the use of hepatitis B surface antigen and hepatitis B e antigen rapid tests to screen women for HBV and assess for tenofovir disoproxil fumarate (TDF) eligibility;
• administration of TDF to eligible women; and
• HBV vaccination among infants at birth (< 2 hours after delivery) then again at 6, 10 and 14 weeks.

For the trial, Segeral and colleagues analyzed data on 1,194 Cambodian women who tested positive for HBV. Of that total, 338 were eligible to receive TDF.

The median age of the women at study enrollment was 29 years, and they had been pregnant for a median of 23 weeks. The median HBV DNA level was 7.9 log10 IU/mL among the women who were eligible to receive TDF compared with 2.5 log10 IU/mL among those who were not eligible.

Ninety-four percent of eligible women were started on therapy with TDF, 14.5% of whom were treated fewer than 4 weeks before giving birth.

Of the women who received TDF, the proportion of those with HBV DNA below 5.3 log10 IU/mL was 90% among those who received treatment more than 4 weeks before giving birth, compared with 50% among those who received treatment fewer than 4 weeks before giving birth (P <. 001), according to the researchers.

After delivery, 86% of infants received the first HBV vaccine dose within 2 hours and 95% received the first dose within 24 hours. In addition, 15% of infants received hepatitis B immunoglobin.

“It is important to note that immunoglobulin were not recommended in our study but could be done when accessible,” Segeral said.

The researchers reported that the rate of mother-to-child HBV transmission was 1.26% (95% CI, 0.34-3.2) among the cohort of infants who received immunoglobulin and 1.48% (95% CI, 0.4-3.74) among those who did not receive immunoglobulin.

In addition, the transmission rate was 0% (95% CI, 0-1.41) among women who received TDF more than 4 weeks before delivery vs. 8.33% (95% CI, 1.75-22.5) among women who received TDF fewer than 4 weeks before delivery.

For the women who were not eligible to receive TDF, the mother-to-child transmission rate was 0.98% (95% CI, 0.4-2.02), and 1.06% (95% CI, 0.39-2.3) in the absence of hepatitis B immunoglobulin.

“This study is the first large study evaluating an immunoglobulin-free strategy using tenofovir prophylaxis,” Segeral said. “This strategy could represent an option to achieve the WHO target of less than 0.1% of HBV equivalents in infants in 2030.”

By Janel Miller

Source: Segeral O, et al. Abstract 28. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 12-16, 2022 (virtual meeting).

All Healio reports from CROI 2022.