Talking About Vaccines with Dr. Paul Offit: News Briefs – May 2018 – New Hepatitis B Vaccine for Adults

News Briefs — New hepatitis B vaccine for adults

Hi, my name is Paul Offit. I’m talking to you today from the Vaccine Education Center here at the Children’s Hospital of Philadelphia.

In October 2017, a novel hepatitis B vaccine was licensed by the Food and Drug Administration. In February of 2018, that same vaccine was recommended for use in people over 18 years of age. This vaccine, this new hepatitis B vaccine, is really fairly dramatically different from the previous two vaccines. So let’s go back to the beginning.

The other two vaccines that are out there are both made essentially the same way, which is that you take the gene that codes for a protein that sits on the surface of hepatitis B virus, called the hepatitis B surface antigen. You put it into a plasmid. That plasmid is then inserted into yeast cells, where that protein is then made by the yeast cells. The protein is then purified, and the vaccine also contains an adjuvant, and adjuvant is something that helps the immune system work better. Either because it allows you to give fewer doses of the vaccine, or it allows you to give lesser quantities of the active ingredient of the vaccine. That’s what an adjuvant is.

Now, both of those other vaccines were made the same way using what I described, something called recombinant DNA technology. They both had the same adjuvant, which was an aluminum salt. This new vaccine is different in one critical way. It’s made the same way in terms of the recombinant DNA technology. It’s still made using the hepatitis B surface antigen but it was this novel adjuvant, which has the fancy name CpG motifs. The ‘C’ stands for cytosine. The ‘G’ stands for guanine, which are these two nucleosides that are part of DNA. Then the ‘P’ just stands for this linkage between the two. What’s novel about that, what’s different than the aluminum salts, is that the CpG motifs are sort of unique to bacterial DNA. Ever since we crawled out of the ocean onto land, our immune systems have been able to recognize bacteria because bacteria have certain features that our human cells don’t have. One is this so-called CpG motif that is seen in bacterial DNA, but is not seen in vertebrate DNA, or said another way, is not seen in our DNA. 

So our immune system immediately responds to it. That’s called the innate immune response. What this CpG motif has done now is it makes a fairly dramatic difference actually in the immunogenicity of the hepatitis B vaccine. This new hepatitis B vaccine’s capacity to induce an immune response against that particular hepatitis B protein is better actually than for those other two vaccines. It’s true of all age groups, even the age group over 70 years of age.

I think this is a useful addition to our hepatitis B vaccine armamentarium. I think it may have a special place for those people who don’t seem to be able to respond to the three doses of the current or previous two hepatitis B vaccines.

So, I think there’s every reason to be happy about this new development in hepatitis B vaccines.

Thank you.