The hepatitis B vaccine is prepared in the laboratory using genetic engineering techniques and contains only a part of the virus, absolutely incapable of producing the disease, but sufficient to trigger the body's defences.
It is administered intramuscularly, alone or together with other vaccinations. Given the high incidence and severity of the risks associated with the disease, it is actively offered free-of-charge to the whole population. Law n° 165/91 sanctioned mandatory vaccination against hepatitis B for all newborns in the first year of life.
When to vaccinate
The vaccine is given in three doses at the 3rd, 5th and 11th month of life.
In the newborn of a mother infected with the hepatitis B virus, the first dose must be administered within 12 hours of birth, and the second dose administered one month later. Subsequent doses are usually administered with the hexavalent vaccine, following the normal schedule.
The vaccine is also recommended for all those at risk (health workers and care staff in hospitals and nursing homes, people living with chronic carriers of the hepatitis B virus, public safety workers, individuals who require numerous blood transfusions, subjects on dialysis etc.).
Who should not be vaccinated
Subjects who had a severe allergic reaction to previous doses of the hepatitis B vaccine or to components of the vaccine.
When to postpone vaccination
People with mild illnesses can generally be vaccinated safely. For subjects who have moderate or severe illnesses, it is advisable to delay vaccination until they have recovered.
Vaccination risks
Like any other drug, vaccines could cause severe allergic reactions, although the risk of such reactions is extremely low; the risk that the hepatitis B vaccine will cause serious damage or death is extremely low, given that severe reactions, such as severe allergic reactions, are very rare (less than 1 in 1,000,000 doses).
The hepatitis B vaccine is a very safe vaccine that does not usually cause problems, although there may be minor problems such as:
- fever (1/3 of children);
- pain, redness and swelling at the injection site (1/5 of cases).
These symptoms generally occur within 48 hours of vaccination and usually last for no more than 48 hours.
In rare cases (1-2 of 10,000), convulsions caused by high fever may occur.