Hepatitis B vaccine was the first to prevent a type of cancer

The HBV virus, which causes hepatitis B, is a silent antigen, which can take years before it is noticed by the host. When this happens, however, the damage caused has often resulted in cirrhosis or liver cancer. Available in the Unified Health System (SUS) for children, adolescents and adults, the hepatitis B vaccine is the main way to prevent this disease, which can be transmitted sexually, through contact with blood and during pregnancy, from mother to the baby.

Infectious disease specialist Raquel Stucchi says that children’s response to the hepatitis B vaccine is 100% – Personal archive

Infectious disease specialist at Campinas State University (Unicamp) and consultant for the Brazilian Society of Infectious Diseases, Raquel Stucchi highlights that the hepatitis B vaccine was the first vaccine against any type of cancer to be made available, because the hepatitis B virus is the main cause of liver cancer.

“Vaccination drastically reduced cases of hepatitis B and the risk of cirrhosis and liver cancer. Therefore, the vaccine is important. And why in childhood? First, adherence in childhood is easier. It is done with other vaccines in the first months of life and can be done in the nursery, as soon as the child is born. And the response of children against hepatitis B is 100%, and, with the child remaining healthy afterwards, this protection is for life.”

Vaccination from birth

Hepatitis B is often thought of as a sexually transmitted infection (STI), but vaccination against the disease after birth is considered essential to ensure that there is no transmission of the virus from mother to baby, which is called vertical transmission in medicine.

Part of the calendar for adults and pregnant women, the hepatitis B vaccine should also be administered to babies soon after birth. The National Immunization Program, which turns 50 in 2023, recommends that newborns receive this vaccine within the first 24 hours of life, and, preferably, within the first 12 hours, while still in the maternity ward.

Doctor Renato Kfouri highlights the importance of children being vaccinated against hepatitis B soon after birth – SBIm/Disclosure

Pediatrician Renato Kfouri, president of the Scientific Department of Immunizations of the Brazilian Society of Pediatrics (SBP) and vice-president of the Brazilian Society of Immunizations (SBIm), explains that this agility guarantees that the baby will not be contaminated by the hepatitis B virus, if your mother lives with the infection.

“By vaccinating at birth, we eliminate this possibility, and, consequently, the possibility of having chronic carriers of this virus in the future. This is the reason to get vaccinated at birth”, explains Renato Kfouri.

He adds that preventing the formation of a chronic condition also contributes to blocking the virus.

The child’s vaccination schedule provides that protection against hepatitis B also occurs through the pentavalent vaccine, which must be administered at 2 months, 4 months and 6 months. In addition to this form of hepatitis, the vaccine prevents diphtheria, tetanus, whooping cough, and Haemophilus influenzae Bcausing a type of meningitis.

From the age of 7, when there is no proof of vaccination against hepatitis B or when the vaccination schedule is incomplete, the recommendation is to complete three doses with the specific hepatitis B vaccine, with an interval of 30 days from the first dose. for the second dose, and 6 months between the first and the third. This recommendation includes adolescents, adults and, especially, pregnant women.

Effects and adverse events

The Brazilian Society of Immunizations reports that, in 3% to 29% of those vaccinated, pain may occur at the application site. Hardening, swelling and redness affect 0.2% to 17% of people.

Post-vaccination patients may also have a well-tolerated and self-limited fever in the first 24 hours after application, for 1% to 6% of those vaccinated. Fatigue, dizziness, headache, irritability and gastrointestinal discomfort are reported by 1% to 20%.

Adverse events more serious than this are considered rare or very rare. Idiopathic thrombocytopenic purpura was recorded in less than 0.01% of those vaccinated, so it was not possible to establish whether it was a coincidence or whether it was in fact related to the vaccination.

The hepatitis B vaccine package insert also predicts a very rare frequency of anaphylaxis in vaccinated adolescents and adults, at a rate of one case in every 600,000. This occurrence is even rarer in children.

Test for diagnosing hepatitis B – Rovena Rosa/Archive/Agência Brasil

One fifth of hepatitis deaths

The Ministry of Health shows that the HBV virus causes up to a third of hepatitis cases reported in Brazil and was related to a fifth of hepatitis deaths between 2000 and 2017. In most cases, the infected person does not show symptoms and is diagnosed decades after infection, with signs related to other liver diseases, such as tiredness, dizziness, nausea/vomiting, fever, abdominal pain, yellowing of the skin and eyes.

Hepatitis B is still considered a disease without a cure, and the treatment available in the SUS aims to reduce the risk of disease progression, which can cause cirrhosis, liver cancer and death. Raquel Stucchi explains that the treatment, with antivirals, lasts a lifetime.

“If you don’t get tested, the person will only discover that they have the virus when they already have advanced cirrhosis or when they develop liver cancer. The diagnosis is easily made, even through rapid tests,” she says.

“To date, we do not have medication that eliminates the hepatitis B virus. Today, we can say that there is no cure, but the vaccine prevents this illness and the need for treatment for the rest of your life.”

After infection, the disease can develop in two forms, acute and chronic. The acute form occurs when the infection lasts for a short period of time, and the chronic form occurs when the disease lasts more than six months. The risk of the disease becoming chronic depends on the age at which the infection occurs, and babies are more likely to have chronic hepatitis in the future.

The most important ways of transmitting hepatitis B are contact with blood and sexual contact without a condom. The infectious disease specialist explains that contact with blood includes carrying out procedures and sharing utensils without the necessary hygiene.

“In blood transfusions, this risk practically no longer exists, due to the screening carried out on donors, but contact with blood includes medical, dental or aesthetic procedures without adequate hygiene. And also manicures, nail clippers without sterilization, tattoos, piercings.”

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