Hepatitis B vaccine has been saving many lives since the day it is introduced. Undoubtedly it is a very effective vaccine and quite popular as well. Yet there are some questions related to hepatitis B vaccination that push panic button in many.

We have brought together all such common queries related to hepatitis b vaccine in this single post. So that instead of hesitating to take this vaccine, people will rather be aware of it. And also they will know exactly how to take this vaccine. 

Is it safe to take hepatitis b vaccine?

Hundreds of millions of people have been vaccinated safely so far with hepatitis b vaccine. And hardly a person developed any dire side effect to it. Common reactions like pain, soreness at site of injection and fever can occur transiently following hepatitis b vaccination.

Allergy or hypersensitivity may ensue post vaccination. But it is extremely rare. A person who has developed allergy previously to hepatitis b vaccine or who has known allergy to yeast should not take this vaccine. 

Can hepatitis vaccine cause hepatitis b disease ?

Hepatitis b vaccine can never cause hepatitis infection or disease. Since the year 1986 this vaccine is mass-produced by recombinant technology. No blood or blood product is used to prepare this vaccine. That makes it so safe. 

The hepatitis b vaccine synthesized by recombinant technology has just surface antigen of hepatitis b virus ( HBsAg ). It doesn’t contain any other component of virus or its genetic material. That is why there is no fear of getting hepatitis b infection from its vaccine.

How hepatitis b vaccine produced by recombinant technology?

Gone are the days when hepatitis b vaccine was manufactured using blood products. These days recombinant technology is used. 

Here genetic material of hepatitis b virus is fused with genetic material of a bacteria named E.Coli. This fused gene is then implanted inside yeast cell. This yeast cell then multiplies to form a number of yeast cells. As these yeast cells have viral gene, they produce viral proteins called hepatitis b surface antigen protein or HBsAg. 

This is then purified to form hepatitis B vaccine. Thus hepatitis B vaccine is nothing but HBsAg. When a person receives hepatitis b vaccine, this HBsAg will enter inside body and trigger production of protective antibodies. These anti-Hbs- antibodies protect specifically against hepatitis B infection. 

How effective is hepatitis B vaccine?

Hepatitis B vaccine is highly effective. An antibody titre of >10 IU/ml after 1-3 months of taking vaccine is enough for protection in a healthy individual. A 3 dose series, provides seroprotection of >95% in healthy population. 

In immuno- compromised person or person with chronic kidney disease and dialysis an anti-HBs-antibody of > 100 IU/ml is reportedly protective. 

What to do if sufficient immunity is not developed after hepatitis b schedule?

In general adults having strong immune system develop adequate immunity after 3 dose series at 0,1 and 6 months for hepatitis b vaccine. Real concern is when a person has poor immunity

In these individuals after 1 – 3 months of completing hepatitis b vaccine, test for antibody titre in blood. If anti-hbs-antibody is <10 IU/ml then it is not protective. In situations like this give a booster dose of hepatitis b vaccine. This is called ‘challenge dose’. Then again recheck antibody after 1 to 3 months. 

If still antibody level is inadequate even after booster then give shots of 3 dose series again. If this first series of repeat vaccination doesn’t help then redo one more 3 dose series.

What if these 2 repeat series also fail? In such instances GMCSF might help. This is given as 250 microgram injection followed by hepatitis b vaccine. Some studies encourage intradermal injection ( injection into skin ) of hepatitis b vaccine. They say injecting vaccine into skin produces good immune response in immuno-compromised individuals. This again needs further research.

After sufficient antibodies generated, every year antibody titres should be checked in immuno-compromised people. If it is waning then booster dose should be inoculated. 

If a person doesn’t achieve sufficient immunity even after following all of the above steps then better to stay away from hepatitis b infected blood and body fluids as far as possible. And in case of accidental exposure each such individual should take hepatitis b immunoglobulin ( antibody ) following the event as soon as possible. 

Can a hepatitis b infected person get protection from vaccine ?

No, a person who is already infected with hepatitis B will not be benefited from vaccine. Hence if you find someone to be HBsAg positive, then refrain from using Hepatitis B vaccine. 

Can a person take hepatitis vaccine after exposure to hepatitis b virus?

If an unvaccinated person get exposed to blood or body fluid of hepatitis B infected person then he can certainly take hepatitis B vaccine soon after that. Preferable time limit is within 24 hours of exposure. This is called “post exposure prophylaxis”.

S/he must take HBIG ( hepatitis b immunoglobulin ), within 24 hours. Vaccine and HBIG should however be injected to distinct sites. 

How long does the effect of Hepatitis B vaccine last ?

Earlier there was this belief that immunity generated due to hepatitis B vaccine lasts for around 8 years. But studies have proven that this immunity lasts for at least 25-30 years. And in most healthy individuals this immunity is lifelong. Hence further booster dose after completion of schedule is not recommended currently.

But if the person has poor immunity or is on dialysis then vaccine induced immunity may decline over time. Thus yearly test for antibody titre is imperative. And booster is advisable in case immunity wanes. 



I hope people find this article over internet and get their doubts cleared. I wish more and more people keep their dilemmas and hesitation aside and are drawn towards taking this vaccine. 

Do you have any query related to hepatitis b vaccine? No matter how small or irrelevant it may seem, do share with us. We will come up with answer to it for sure. 


All the informations provided here are for educational and awareness purpose only. Kindly do not use these as alternative to medical consultation.

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