The leading cause of liver cancer worldwide is hepatitis B virus (HBV). Sierra Leone is thought to have a high percentage, at least 8%, of the population actively infected with HBV. Some studies report that in Sierra Leone, 6% to 11% of pregnant women have active HBV infection, which they can transmit to their babies during birth. When people are infected with HBV early in life (newborns, infants and early childhood), they are more likely to become actively infected and to develop liver cancer from the virus. There is no cure for HBV infection so those infected can require medications for the rest of their life. The good news is that HBV infection is preventable with an effective hepatitis B (HepB) vaccine.
The World Health Organization (WHO) recommends that infants receive the first dose of HepB vaccine within 24 hours of birth known as the ‘birth dose’, followed by 2 or 3 additional shots to ensure lifelong protection. Providing a birth dose prevents the early transmission of HBV from mother to child. The government of Sierra Leone provides the HepB vaccine to infants at 6, 10, and 14 weeks of age, but does not yet provide the birth dose. I recently had my first child, and I’m keenly aware that access to vaccines here in the United States means I’m able to protect my child from vaccine preventable diseases, such as hepatitis B. Parents in countries like Sierra Leone aren’t as fortunate, since some vaccines just aren’t yet available to them.
Science helps make public health decisions
CDC is helping control of HBV infection in Sierra Leone by conducting a survey to look at how commonly mother-to-child transmission of HBV occurs during infancy and how well the current infant hepatitis B vaccination program is preventing disease in children. Findings will inform the Sierra Leone Ministry of Health and Sanitation on the need to administer the HepB vaccine at birth, which could help prevent future generations from getting liver disease and liver cancer. The survey will also inform the risks of mother-to-child transmission of HBV in other parts of Africa with similar HBV strains (genotypes) as Sierra Leone. Survey results will help governments decide whether to provide a birth dose of HepB.
Last year, I visited Sierra Leone five times, spending over 100 days in country working with the Ministry of Health and Sanitation, Statistics Sierra Leone, eHealth Africa, the University of Makeni, UNICEF and the WHO to implement the HepB survey.
Before we implemented the survey, Statistics Sierra Leone listed all of the households in 212 areas in Freetown, Bo, and Bombali districts. This allowed us to identify households that had children aged 4 to 30 months old or 5 to 9 years old. Once we had a list of all the households with children in the age groups we needed, we randomly selected households to visit in each area to enroll children and their mothers.
Thirteen teams collected the information. Teams included surveyors and supervisors from Statistics Sierra Leone and phlebotomists from the National Blood Bank. The phlebotomists tested the children and their mothers for active HBV infection.
Community involvement thanks to determined teams
Each day a survey team went to a pre-selected area to identify the families that they needed to interview and test. Before they could start work, the teams spoke to the village chief to obtain his permission.
At each home, the teams explained the purpose of the survey, asked parents’ permission to test their child, and found out information about the child’s vaccination history. The phlebotomist tested the child by collecting a few drops of blood from a finger prick and placing the blood on a rapid test strip. Team supervisors provided the parents with the child’s test result within 15 minutes.
After that, the teams tested mothers of young children for active HBV infection using a rapid test, and asked them to provide some demographic information and information about their risk of being infected.
Some mothers were also asked to provide venous blood samples (taken via syringe in the arm) for additional laboratory testing. These tests will help determine if certain levels of HBV in the blood or certain HBV strains are more likely to lead to HBV transmission from the mother to the infant.
Phlebotomists processed the venous blood samples in the team vehicle, where they used a portable centrifuge to separate serum from the blood. The serum was stored in a portable fridge until the district supervisor was able to transport the samples to the district freezer.
Each of the 13 teams had on average, 18 areas to visit, testing up to 12 houses every day. The teams worked incredibly hard to complete the data collection despite many varied challenges. One team had to wade across a river to reach a village. Several others teams had to work with their district health management teams in order to reassure communities of the importance of the survey and dispel fears of providing blood given the recent history of Ebola in the region.
By the end of the survey, the teams had visited almost 4,500 families, tested over 1,800 children aged 4 to 30 months old and almost all of their mothers. Teams also tested over 2,000 children aged 5-9 years old, for active HBV infection. CDC is testing the blood samples and analyzing the data, and expect that results will be available before the end of 2019.
Although I spent a lot of time away from my family, this important work will hopefully increase access to HepB vaccine birth dose in Africa. It would not have been possible without the collaboration from many agencies and communities.
Story Source: CDC Blog
