MTCT / hep A vaccine

Hi all, I have a question to a specialist regarding protection of my child. I discovered last year that I am a chronic hbv carrier (I was vaccinated as a teenager so I guess that I caught it somehow as a child).
I have a 2 month old baby that got a vaccine + immunoglobuline 2h after birth.
5 days ago I got a flu and hep A vaccine (I was very worried of catching it and the impact on my liver).
After the vaccine my hepatologist mentioned that I should not brestfeed for 2 weeks, which wasn’t said by the other doctor so I breastfed all this time.
I am very worried and have a few Qs and would greatly appreciate your response.

  1. Could a HBA vaccine have any impact on how the baby will respond to the hbv protection, eg. Increase a chance of him being infected?
  2. is there any risk in breastfeeding (according to my research it’s OK, but no clinical studies)? Probably the hepatologist just wanged to be super safe.
  3. for the last 3 days (2 days after the vaccinations), I am slightly feverish (37.5-38) and have a strong nausea. Is it related to the HBA vaccine (eg. Liver response)?

I am currently very stressed and want to thank you for this forum and support to so many people.
Cheers and best regards,

Edit: just to add, the baby seems to feel good, no fever, no other issues.

Dear @Question123,

I have taught the HAV material to our med students for over 2 decades, so hopefully some of this info will be helpful.

I’ve never heard of a recommendation not to breastfeed after an HAV vaccination. That vaccine is a killed whole-virus preparation that cannot replicate in people, and hence vaccination cannot transmit HAV to you or your baby. It is remotely possible that inflammatory cytokines triggered by the vaccine could be transmitted in your milk and cause a mild inflammatory reaction in your child, but I’ve never heard of this and don’t think its a really worry.

The HAV vaccine will have no effect at all on efficacy of the HBV vaccine in your child.

Feeling mildly feverish after a vaccination is normal for many vaccines. The vaccine’s job is to trigger the immune system to make a vigorous response to whatever is in the vaccine. The slight fever just means your immune system is doing what it was told to do. Your response is to the vaccinations and has nothing to do with your chronic HBV infection.

Please don’t be stressed. This is normal preventative medical care and you are doing the very best for your baby. S/he is lucky to have a Mom who cares so much.



Dear John,
Thank you so much for your response and sharing your expertise.
It is really a wonderful news and a huge relief for me.

On this occasion, I wanted to thank once again you, other experts and all community members for creating such a great space. It really makes a difference in lives of many people and I hope that you feel our gratitude every day.

Best regards,


Hi @Question123,

I just wanted to add a couple of specific points to @john.tavis’ great response.

The HAV vaccine is commonly given with the HBV vaccine within the same dose (as Twinrix) and is effective at generating protective responses. So the stimulation of the protection of one virus will not adversely affect the protection of the other.

Yes, breastfeeding is recommended as the risk of HBV transmission through this route is low compared to the benefits of breastfeeding.


Hello I agree completely with Dr. Tavis and Dr. Tu about the Hepatitis A Virus (HAV) vaccine. I am a hepatologist and often see patients living with hepatitis B during their pregnancy. I always encourage breastfeeding and recommend the HAV vaccine.
Enjoy the time with your new baby.
All the best
Carla Coffin

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I agree with my colleagues. Maybe there was a mixup with recommendations of the yellow fever vaccine. The yellow fever vaccine is a so called attenuated „live“ vaccine and for the yellow fever vaccine (and the small pox vaccine) it is not recommended to breast feed for a specific period (usually 2 weeks) after the vaccination since there were a few reports of some transmission to the child.

The regular Flu and Hep A vaccine are both inactivated vaccines and thus these vaccines bare no risk of transmission.

Jochen Wettengel

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