Thread by @babbymd

Alright, folks. With all the talk of measles lately, the MMR has been covered pretty well recently, but I’ve noticed a lot of misinformation circulating about Hepatitis B. Let’s talk about the Hep B vaccine and why we recommend it for newborns and babies.

Hepatitis B is a virus, and an extremely hardy one. Although many people think of it as a disease transmitted sexually or through contaminated needles, it can be transmitted through many bodily fluids and can persist on surfaces—outside the human body!—for up to seven days.

Although the virus can be transmitted through sex or needle sticks, it can also be passed from mother to baby perinatally, through shared items like toothbrushes or razors, or contact with open wounds with an infected person.

Because Hep B often does not cause symptoms in adults, many of us likely have close contacts who are infected with Hep B and capable of transmitting it to others without knowing it. There are areas of the world with infection rates as high as 7%.

Healthy adults frequently clear their Hep B infections and become immune. Some will develop chronic infection that causes cirrhosis and liver failure or liver cancer. Some will die. Some will pass the virus on to others.

Infants, however, are much more vulnerable to acute, life-threatening hepatitis. As many as 90% of infants who contract Hep B will suffer from chronic infection, risk of liver failure or liver cancer, death. And of course in turn be capable of infecting others.

So to recap: WHY do we vaccinate newborns and infants?
1) Hep B is very contagious and can persist on surfaces for up to a week
2) Can be spread by close contacts, who may not even know they have Hep B
3) Babies much more likely to die of acute disease or have chronic Hep B

How does the Hepatitis B vaccine work?

The virus itself has a very recognizable protein on its surface, which helps the immune system recognize Hep B and defend against infection. The vaccine exposes the immune system to this protein, without introducing the rest of the virus.

What this means is 1) the Hep B vaccine CANNOT infect someone with Hep B; the virus isn’t in the vaccine.
2) Because only a small part of the virus is shown to the immune system, it has to be reinforced several times with subsequent vaccines and may not confer lifelong immunity.

However, most people are protected with lifelong immunity. Some unlucky ducks have to get boosters if tests show they no longer make the antibodies to the protein in the vaccine. The vaccine is very safe and is extremely well-tolerated by even small babies.

1) Hep B is easy to catch, even without sexual contact or use of needles
2) Infants are at much higher risk of death and lifelong disease from infection, including cancer, than the general population
3) The vaccine is very safe and has been successful at reducing disease burden🌎