https://youtu.be/iBGI4RkH_OQ 8th Asian Congress of Pediatric of Infectious Disease 8th - 10th November 2016 Queen Sirikit National Convention Center Bangkok Thailand
8th Asian Congress of Pediatric of Infectious Disease 8th - 10th November 2016
Queen Sirikit National Convention Center
Bangkok Thailand 1. Dr. Beasley was the first to discover of a virus that leads to human cancer. Beasley and his colleagues proved that hepatitis B virus (HBV) is a primary cause of liver cancer, and that a path of transmission is from mothers to infants during childbirth.
Working in Taiwan he concluded that 1 in 4 male carries of Hepatitis B would die of hepatocellular carcinoma
2. I work in India
India has a population 50 times larger than Taiwan. 4% are hepatitis B carriers.
3. That means 250,000 would die each year in India from HCC.
Data from the ICMR cancer registry suggests that only 5000 actually die of the cancer in India.
Why that is so is not clearly understood. It is said to be due to differences in the strain of the virus
Strain A and D in India and B and C in Taiwan.
4. HCC develops in chronic carriers of Hepatitis B meaning the body cannot get rid of the infection
90% of babies who acquire hepatitis at birth become chronic carriers.
Only 2% of those who get hepatitis B as adults become chronic carriers.
So vaccination is advised starting at birth to prevent mother to child transmission
40% deliveries in India outside medical institutions and are very difficult to reach.
We have adopted a pragmatic approach of vaccinating hospital born babies at birth but others are vaccinated at 6 weeks with DPT immunization
5. We conducted a case control study to find out if birth dose was crucial.
We examined children who were HBsAg carriers and those who got infection and which they cleared with Anti-HBcAb. We looked to see if they were vaccinated at birth, or later or if they received no vaccine at all
6. We looked at antibody to surface antigen to see if they took up the vaccine
7. Of the 2671 children 59% were fully immunized and 56%% of them had received the birth dose
8. There was and no reduction in carrier rate or in the infection rate in those vaccinated at birth compared to other vaccinated babies who had not received the birth dose.
9. Protective antibody to surface antigen was present only in 70% of those fully vaccinated. We expect at least 90% protection
Among the unvaccinated 40% were immune.
This must be passively acquired immunity from mothers. As the mothers are unvaccinated it must reflect antibodies acquired by mothers after natural infection
10. The antibody to surface antigen in the unvaccinated reduced with age suggesting again that this is passively acquired immunity from mothers and that it declines slowly.
The high levels of antibody in unimmunised babies was previously documented in another ICMR study by Aggarwal et al
11. Remember we started by saying the incidence of HCC in India is much smaller than expected.
Now we probably have the answer.
The A and D strains are easily transmitted.
Most mothers who were unimmunized have got natural infection and have developed antibodies.
This is passively transmitted to babies and babies are protected in the first year when the chance of HCC is worst. Later this immunity wanes and the child gets natural infection and develops antibodies that are passed on for protection of the next generation from HCC.
This new hypothesis will need to be validated by others
12. High Levels of Natural HBsAb in Newborns in India May Provide Protection against Hepatocellular Carcinoma
On behalf of the study team
13. Thank you