Commonly asked questions about the Twinrix Vaccine for Hepatitis A and B
The Twinrix vaccine is a combination vaccine that provides protection against hepatitis A and hepatitis B. It is administered as a series of three injections over a 6-month period. The vaccine is recommended for adults who are at increased risk of infection with these viruses, such as healthcare workers, travelers to certain countries, and individuals with certain medical conditions. It is highly effective at preventing hepatitis A and B, and can help prevent the spread of these diseases.
What are the risks with the Twinrix vaccine?
As with all vaccines, there is a very small risk of experiencing a severe allergic reaction to the Twinrix vaccine. This reaction, known as anaphylaxis, is rare and can be treated effectively with medication. Other possible side effects of the vaccine may include pain, swelling, or redness at the injection site, fever, headache, and muscle aches. These side effects are usually mild and resolve on their own within a few days. It is important to discuss the potential risks and benefits of the vaccine with your doctor before getting vaccinated.
Can I get the Twinrix if I've had Hepatitis B vaccination before?
Yes, it is possible to get the Twinrix vaccine even if you have previously received a vaccination for hepatitis B. The Twinrix vaccine provides protection against both hepatitis A and hepatitis B, so if you have previously been vaccinated for hepatitis B, the Twinrix vaccine can provide additional protection against hepatitis A.
Why does my Hepatitis B titre show no antibodies even after completing the Twinrix series?
The Twinrix vaccine protects against both Hepatitis A and Hepatitis B. However, some individuals may not develop full immunity to Hepatitis B even after completing the full vaccine series.
This can happen for several reasons, including:
Differences in individual immune response
Incomplete vaccination series or incorrect timing between doses
Waning immunity over time
If your blood test (anti-HBs titre) shows no detectable antibodies:
A single booster dose of a Hepatitis B–containing vaccine (e.g., Engerix-B, Recombivax HB, or Twinrix) is typically recommended first.
Repeat blood testing is done 1 to 2 months after the booster to check for an adequate immune response (protective level ≥ 10 mIU/mL).
If your antibody level remains low or negative after this booster, the usual recommendation is to repeat the full Hepatitis B series (three doses, given at 0, 1, and 6 months).
After the repeat series, blood testing is again performed 1–2 months after the final dose.
A small percentage of people are true non-responders - they do not develop protective antibodies even after two complete vaccine series.
If you have received Twinrix or Hepatitis B vaccines and your bloodwork still shows no immunity, we recommend:
Discussing this with your family physician or the clinic where you were vaccinated, to arrange a booster and follow-up testing.
Alternatively, you can book a vaccination consultation through TeleTest to request a booster.
What happens if I’m still not immune after two full Hepatitis B vaccine series?
If your blood test still shows no antibodies after two complete vaccine series, you’re considered a “non-responder.”
This means your body doesn’t form protective immunity even after being fully vaccinated - and that’s okay, it happens to a small number of people.
Here’s what you should know:
You won’t need more vaccine doses. Extra doses beyond two full series usually don’t help your body build protection.
Your doctor may order additional blood tests to make sure you don’t already have Hepatitis B (by checking for markers of past or current infection).
If those tests are negative, you’re considered susceptible - meaning you can still catch Hepatitis B if exposed.
If you’re ever exposed to the virus (for example, through a needle injury or unprotected contact), you’ll need an injection of Hepatitis B immune globulin (HBIG) as soon as possible - ideally within 24 hours - to give temporary protection.
It’s a good idea to keep a record of your vaccine history and “non-responder” status, so healthcare providers can act quickly if you’re ever exposed.
