Example of a purified antigen vaccine, the hepatitis B vaccine is particularly recommended for young children and unvaccinated adults who, for some reason, are at risk of contracting the hepatitis B virus (ie HBV) on a daily basis.
Carried out by intramuscular injection, the administration of the hepatitis B vaccine is foreseen in a course of 3 doses for recipients of all ages.
Available on the market in various formulations, the hepatitis B vaccine is a drug with reduced adverse effects (the most common are minor clinical disturbances) and effective.
Currently, the vaccine against hepatitis B is subject to the vaccination obligation established in the summer of 2017; consequently, it is mandatory for all newborns.
What is Hepatitis B: a brief review
"Hepatitis B is a" particularly contagious infection, due to the HBV virus (or hepatitis B virus or simply HBV), which is a double-stranded DNA virus belonging to the family of Hepadnaviridae.
Transmissible through the blood and body fluids (eg saliva, sperm, vaginal discharge, etc.) of an infected person, "hepatitis B primarily affects the liver. It mainly damages the liver (" hepatitis "means" inflammation of the liver "), resulting in sometimes resulting in serious complications.
Hepatitis B has a very long incubation time: in fact, it can range from a minimum of 45 days to a maximum of even 160 days.
Hepatitis B is often asymptomatic, in both children and adults; when symptomatic, it typically presents with jaundice, loss of appetite, nausea, vomiting, dark urine, pale stools, fatigue, abdominal pain where the liver and joint pain.
The presence or absence of symptoms is not indicative of the severity of the infection.
Hepatitis B tends to have a benign course; however, in some unfortunate situations, especially if the patient is a child or an adult with immune deficiency, it can cause severe liver damage and lead to very severe complications.
chronic and / or end-stage renal disease (e.g. renal failure);The hepatitis B vaccine can also be obtained by non-immunized adults who do not fall into any of the above categories and who simply wish to protect themselves from HBV.
When we speak of pregnant women who test positive for "hepatitis B s" we mean women who have contracted HBV infection during pregnancy.
Why get vaccinated against Hepatitis B?
The reasons why the medical community and the Ministry of Health recommend (and in some make it mandatory) the hepatitis B vaccine are different; here are the main ones:
- Hepatitis B can degenerate and take on the characteristics of a chronic infection (lasting more than 6 months); when this happens, hepatitis B becomes a potential cause of very serious conditions such as liver cirrhosis, liver cancer (hepatocellular carcinoma) and liver failure.
- The risk of hepatitis B becoming a chronic infection (with all consequences of the case) is greater in children born to hepatitis B positive mothers, in children aged 0 to 5 years, and in adults with immune deficiencies ( eg: diabetics, AIDS patients) and / or with chronic renal failure.
- Hepatitis B has a probability of becoming a chronic infection equal to: 90%, in children within the first year of life; 30-50%, in children aged 1 to 5 years; 20-40%, in adults in poor health conditions (eg: renal failure, AIDS, diabetes).
- About 25% of people with a chronic form of hepatitis B die prematurely from liver cirrhosis or liver cancer.
- According to some estimates, people who have developed chronic form of hepatitis B are up to 300 times more at risk of liver cancer than a healthy person.
- In "1-2% of those affected," hepatitis B is responsible for an "infection so acute that it causes a" fulminant liver failure, the existence of which is fatal (fulminant hepatitis B).
Pregnancy Hepatitis B Vaccine
The hepatitis B vaccine is a vaccine that can be performed in pregnancy (as it is safe for the fetus), but not routinely recommended.
It is recommended, in fact, only in mothers at risk of HBV infection (eg mothers who work as nurses and as doctors; mothers who travel to a country in the world where hepatitis B is endemic).
When is the Hepatitis B Vaccine not needed?
Individuals already vaccinated and all those who have contracted hepatitis B in the past do not need the hepatitis B vaccine.
The hepatitis B vaccine is not a necessity even for unvaccinated adults who do not fall into any risk category; however, given that it is a safe and effective vaccine, experts believe that, in this specific situation, it is still worth pursuing.
, toxins, etc.) inactivated and not dangerous, but still capable of eliciting an immune response.
Types of Hepatitis B Vaccine
Currently, the hepatitis B vaccine is available:
- In monovalent formulation (HBVAXPRO). It exists in dose for pediatric use and in dose for use in adolescents (16 years and older) and adults.
- In combination with the hepatitis A vaccine (Twinrix). It exists in doses for pediatric use and in doses for use in adolescents (16 years and older) and adults.
- In a pentavalent vaccine formulation, also including the anti diphtheria, anti tetanus, anti pertussis, anti poliomyelitis (or anti Haemophilus influenzae type B).
- Combined with diphtheria, tetanus, pertussis, polio and anti vaccines Haemophilus influenzae type B, in what is the vaccine preparation also known as the hexavalent vaccine (INFANRIX HEXA). In this vaccine formulation, the hepatitis B vaccine and all other vaccines are in doses for pediatric use only.
In immunology, any foreign substance capable of triggering the immune system is called an antigen.
In the case of vaccines with purified antigens, the antigens are essentially fragments of the infectious agent against which the immunization is to be obtained, deprived, in the laboratory, of the ability to cause the related infection (NB: this is true provided that the subject is a healthy person, without immune deficiencies).
Antibodies, on the other hand, are proteins that the immune system of the human organism produces whenever it comes into contact with an antigen and which serve to neutralize the latter in the immediate and also in the future, should a second exposure to the same antigen occur.
Thanks to the hepatitis B vaccine, therefore, antibodies against HBV are created, exploiting parts of the latter that are sufficient to stimulate the immune system, but not as sufficient to cause the associated infectious disease.
anti hepatitis B (these are antibodies directed against HBV; they do not correspond to a vaccine).
Did you know that ...
The test for hepatitis B is one of the various laboratory tests routinely scheduled during pregnancy and, in Italy, offered free of charge by the National Health Service starting from the 3rd trimester.
Does the Hepatitis B Vaccine have Boosters?
For healthy individuals, the hepatitis B vaccine does not require boosters.
Method of administration of the Hepatitis B vaccine
The hepatitis B vaccine is administered by intramuscular injection.
In children up to 1 year of age, the injection site is the upper-latero region of the thigh; in older children, adolescents and adults, however, it is on the upper arm.
A special syringe is used for the administration of the hepatitis B vaccine.
Can the Hepatitis B Vaccine be administered together with other Vaccines?
Scientific studies have shown that the hepatitis B vaccine does not interact with other vaccine preparations; this means that it can be administered together with other vaccines.
).However, it should be noted that, most of the time, the adverse effects found are minor clinical disturbances and that the most serious adverse effects are a real rarity.
We must not forget that the risk associated with any type of vaccine, including that against hepatitis B, is decidedly lower than the risk behind the infection against which immunization is to be obtained.
So, in essence, the hepatitis B vaccine can be considered a safe and convenient drug in terms of risk / benefit ratio.
Did you know that ...
Vaccines are drugs that have passed all full-scale security checks.
The various theories according to which they contained substances dangerous for the human being have been, over time, the subject of appropriate scientific studies, which have amply demonstrated their groundlessness.
What are the Adverse Effects of Hepatitis B Vaccine?
Common adverse effects of the hepatitis B vaccine are:
- Pain at the injection site (3-29% of recipients *);
- Headache (3% *);
- Injection site redness (3% *);
- Swelling at the injection site (3% *);
- Fever above 37.7 ° C (1-6% *);
- Tiredness and malaise;
- Irritability and decreased appetite;
- Somnolence and sleep disturbances.
Rare, if not very rare, adverse effects of the hepatitis B vaccine are:
- Allergic reaction to a substance contained in the vaccine (1 every 1,000,000 administrations *);
- Swollen lymph nodes
- Arthralgia (pain in the joints).
*: are epidemiological data obtained from the site of the "Istituto Superiore di Sanità".
How to recognize allergic reactions to Hepatitis B vaccine?
Any allergic reactions to the hepatitis B vaccine occur within minutes of vaccination (this is why parents, after administering the preparation, are asked to stay another 20-30 minutes at the vaccine center) and include symptoms and signs such as: hives, difficulties respiratory tract, swelling of the face, tachycardia and / or paleness.
After the hepatitis B vaccine, in the presence of symptoms or signs of an allergic reaction, it is good to contact a doctor immediately or go to the nearest hospital.
(however, it is still a good idea to inform the doctor of the present situation).
