Hepatitis B is caused by a DNA virus belonging to the family of hepadnaviridae.
The disease often presents with not very specific disorders such as abdominal discomfort, nausea, vomiting and, at times, in 30-50% of acute infections in adults and in 10% of children, with yellow coloring of the skin and the whites of the eyes (jaundice) accompanied by mild fever.
The disease can become persistent over time (chronic) and the risk of this happening increases as the age in which one becomes infected decreases: if the infection occurs at birth, or in the first weeks of life, chronicization occurs in about 90% of those affected. Chronic hepatitis, in 20% of cases, can turn into liver cirrhosis within a few years. Another frequent complication of the disease, especially if cirrhosis is present, is liver cancer (hepatocellular carcinoma).
The source of infection is individuals with ongoing disease and chronically ill patients. In them the virus is present in the blood and in other biological fluids such as saliva, bile, nasal secretions, sperm, vaginal mucus.
Transmission can also occur through transfusions of blood or blood products contaminated by the virus, through cuts and punctures with infected needles or instruments, sexually, perinatally, from the infected mother to the child. Furthermore, since the virus resists on surfaces for several days, the infection can also occur through minimal lesions of the skin or mucous membranes (inapparent parenteral route) that come into contact with contaminated objects such as, for example, toothbrushes, scissors, razors, combs, etc. (Video).How the hepatitis B vaccine is made
How the hepatitis B vaccine is made
The hepatitis B vaccine (read the Buffalo) is a sterile suspension containing particles of the hepatitis B virus surface antigen (HBsAg) produced in the laboratory, in yeast cells, by genetic engineering techniques.
Containing only a part of the virus, it is absolutely unable to produce the disease but is sufficient to induce the response of the body's defense system (immune system).
In addition, there is a combined vaccine against hepatitis A and hepatitis B on the market that is used to protect the body from both viruses at the same time (read the Bufala). It is administered by intramuscular injection, alone or together with other vaccinations.Effectiveness of the vaccine
Effectiveness of the vaccine
The hepatitis B vaccine is 95% effective. The duration of protection is very long and, according to the thirty-year data on the use of this vaccine, it should last for a lifetime (read the Hoax).When to get vaccinated
When to get vaccinated
The vaccine is given to babies in three doses at the third, fifth and eleventh month of life. Also for adolescents and adults, vaccination includes 3 doses, the second after one month from the first and the third after 6 months.
Babies born to mothers infected with hepatitis B virus should be given the first dose within 12 hours of birth at the same time as the injection of specific anti-HBs immunoglobulins into another area of the body. The second dose will be administered one month after the first and the following ones, generally, on the occasion of the hexavalent vaccination, following the normal vaccination schedule.
Furthermore, the vaccine is recommended for all people at risk (health workers and nursing home staff, people living with chronic carriers of the hepatitis B virus, public safety workers, people who need numerous blood transfusions, individuals on dialysis etc.) ..
Since it is a vaccine consisting simply of a component of the virus, it can also be administered to pregnant women.Who does not have to get vaccinated
Who does not have to get vaccinated
The hepatitis B vaccine should not be used in people with known hypersensitivity to its components or in individuals who have already had reactions after previous administration.
When to postpone vaccination
People with mild illnesses can, in general, be safely vaccinated. Individuals who have moderate or severe illnesses must wait for recovery before undergoing the vaccination.Vaccine side effects
Vaccine side effects
The hepatitis B vaccine is very safe and usually causes no problems. In some cases, mild discomfort may appear such as:
- fever (1/3 of children)
- pain, redness and swelling at the injection site (1/5 of cases)
These disorders usually occur within 48 hours of vaccination and last no longer than 48 hours.In rare cases (1-2 in 10,000), seizures related to high fever may occur.
It cannot be excluded that vaccines, like any other drug, may cause severe allergic reactions, even if the risk of this happening is extremely low. In the case of the vaccine against hepatitis B, the reactions are very rare (less than 1 case in 1,000,000 doses). Not being able to exclude them completely, after the administration of each vaccine it is advisable to stay for about half an hour at the vaccination center.Where to find the vaccine
Where to find the vaccine
Given the high frequency and seriousness of the risks associated with the disease, the law n ° 165/91 sanctioned the compulsory vaccination against hepatitis B for all newborns in the first year of life.
The vaccine is offered free of charge to the entire population at vaccination centers throughout Italy and can be purchased in pharmacies.Bibliography
Michael GB et al. Antibody Levels and Protection After Hepatitis B Vaccine: Results of a 30-Year Follow-up Study and Response to a Booster Dose. Journal of Infectious Diseases. 2016; 214: 16-22
EpiCentro (ISS). Useful information on vaccinations
Ministry of Health. National vaccination prevention plan 2017-2019