How can I prevent hepatitis B in children?

Prevention of hepatitis B in children consists primarily of a thorough examination of all categories of donors with mandatory blood testing for HBsAg at each donation using highly sensitive methods of its identification (ELISA, RIA), as well as determination of ALT activity.

Persons who have had viral hepatitis in the past, patients with chronic liver diseases, and persons who have received transfusions of blood and its components in the last 6 months are not allowed to donate. It is prohibited to use blood and its components from donors who have not been tested for HB,Ag for transfusion.

To improve the safety of blood products, it is recommended to test donors not only for HBsAg, but also for anti-HBc. Exclusion from donation of persons with anti-HBc, considered as latent carriers of HBsAg, practically excludes the possibility of transfusion-transmitted hepatitis B.

To prevent infection of newborns, all pregnant women are tested twice for HBsAg using highly sensitive methods: when registering a pregnant woman (8 weeks of pregnancy) and when applying for maternity leave (32 weeks). If HBsAg is detected, the question of carrying the pregnancy to term should be decided strictly on an individual basis. It is important to consider that the risk of intrauterine infection of the fetus is especially high if the woman has HBeAg and is negligible if she does not, even if HBsAg is detected in high concentrations. The risk of infection of the child is also significantly reduced during delivery by caesarean section.

Interruption of infection transmission routes is achieved by using disposable syringes, needles, scarifiers, probes, catheters, blood transfusion systems, and other medical instruments and equipment used in procedures involving damage to the integrity of the skin and mucous membranes.

All reusable medical instruments and equipment must be thoroughly cleaned and sterilized after each use.

Strict adherence to the indications for hemotherapy is of great importance for the prevention of post-transfusion hepatitis. Transfusion of preserved blood and its components (erythrocyte mass, plasma, antithrombin III, factor VII concentrates) is done only for vital indications and is noted in the medical history. It is necessary to switch to transfusion of blood substitutes whenever possible or, as a last resort, transfuse its components (albumin, specially washed erythrocytes, protein, plasma). This is due to the fact that plasma pasteurization (60 °C, 10 h), although it does not guarantee complete inactivation of HBV, still reduces the risk of infection; the risk of infection during transfusion of albumin, protein is even lower and the risk of infection during transfusion of immunoglobulins is negligible.

In high-risk departments for hepatitis B infection (hemodialysis centers, resuscitation units, intensive care units, burn centers, oncology hospitals, hematology departments, etc.), hepatitis B prevention is achieved through strict adherence to anti-epidemic measures: the use of disposable instruments, assigning each device to a fixed group of patients, thorough cleaning of complex medical equipment from blood, maximum isolation of patients, limitation of parenteral interventions, etc. In all these cases, HBsAg identification is carried out using highly sensitive methods and at least once a month.

To prevent occupational infections, all employees must wear rubber gloves when working with blood and strictly adhere to personal hygiene rules.

To prevent the spread of infection in families of hepatitis patients and HBV carriers, routine disinfection is carried out, personal hygiene items (toothbrushes, towels, bed linen, washcloths, combs, shaving accessories, etc.) are strictly individualized. All family members are explained under what conditions infection can occur. Medical supervision is established for family members of patients with chronic hepatitis B and HBsAg carriers.

Specific prevention of hepatitis B is achieved through passive and active immunization of children at high risk of infection.

For passive immunization, immunoglobulin with a high content of antibodies to HBsAg is used (titer in the passive hemagglutination reaction 1:100,000-1:200,000). Such immunoglobulin is obtained from the plasma of donors in whose blood anti-HBs are detected in high titer.

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Indications for immunoglobulin prophylaxis of hepatitis B in children

• Children born to mothers who are carriers of HBsAg or who contracted acute hepatitis B in the last months of pregnancy (immunoglobulin is administered immediately after birth, and then again after 1, 3 and 6 months).
• After virus-containing material enters the body (blood or its components are transfused from a patient or carrier of HBV, accidental cuts, injections with suspected contamination with virus-containing material). In these cases, immunoglobulin is administered in the first hours after the suspected infection and after 1 month.
• In case of a long-term infection risk (children admitted to hemodialysis centers, patients with hemoblastoses, etc.) - it is administered repeatedly at different intervals (after 1-3 months or every 4-6 months). The effectiveness of passive immunization depends primarily on the timing of the immunoglobulin administration. When administered immediately after infection, the prophylactic effect reaches 90%, within 2 days - 50-70%, and when administered after 5 days, immunoglobulin prophylaxis is practically ineffective.

With intramuscular administration of immunoglobulin, the peak concentration of anti-HBs in the blood occurs after 2-5 days. To obtain a more rapid protective effect, immunoglobulin can be administered intravenously.

The period of immunoglobulin elimination varies from 2 to 6 months. A reliable protective effect is observed only in the first month after administration, therefore, to obtain a prolonged effect, repeated administration of immunoglobulin is necessary. In addition, the use of immunoglobulin is effective only with a low infective dose of HBV. In the case of massive infection (blood transfusion, plasma, etc.), immunoglobulin prophylaxis is ineffective.

Despite the shortcomings, the introduction of specific immunoglobulin can take a worthy place in the prevention of hepatitis B. According to the literature, timely introduction of specific immunoglobulin allows preventing hepatitis B infection in 70-90% of vaccinated people.

Hepatitis B vaccination for children

Genetically engineered vaccines are used for active prevention of hepatitis B.

In our country, several recombinant vaccines against hepatitis B have been created (manufactured by ZAO Combiotech and others). In addition, several foreign drugs have been registered and approved for use (Engerix B; HB-VAXII, Euvax B; Shenvac-B; Eberbiovac AV, Regevak B, etc.).

Active immunization against hepatitis B is required for:

• all newborns in the first 24 hours of life, including children born to healthy mothers and children from risk groups, which include newborns born to mothers who are HBsAg carriers, who have viral hepatitis B or who have had viral hepatitis B in the third trimester of pregnancy, who do not have the results of testing for hepatitis B markers, as well as those assigned to risk groups: drug addicts, in families in which there is an HBsAg carrier or a patient with acute viral hepatitis B and chronic viral hepatitis;
• newborns in areas endemic for hepatitis B, with an HBsAg carriage rate of more than 5%;
• patients who frequently undergo various parenteral manipulations (chronic renal failure, diabetes mellitus, blood diseases, planned surgery using an artificial blood circulation machine, etc.);
• persons in close contact with HBsAg carriers (in families, closed children's groups);
• medical personnel of hepatitis departments, hemodialysis centers, blood service departments, surgeons, dentists, pathologists;
• persons who have received accidental injury from instruments contaminated with the blood of patients with hepatitis B or HBsAg carriers.

Hepatitis B vaccination is administered three times according to the schedule 0, 1, 6 months, for healthy children - 0, 3, 6 months. Other schedules are also acceptable: 0.1, 3 months or 0.1, 12 months. Revaccination is administered every 5 years.

Only persons whose blood does not contain HBV markers (HB, Ag, anti-HBc, anti-HBs) are subject to active immunization. If one of the hepatitis B markers is present, vaccination is not performed.

The effectiveness of vaccination against hepatitis B is very high. Numerous studies show that when the vaccine is administered according to the 0.1.6 month schedule, 95% of people develop protective immunity, providing reliable protection against HBV infection for 5 years or more.

There are no contraindications to vaccination against hepatitis B. The vaccine is safe and areactogenic. Vaccination can reduce the incidence of hepatitis B by 10-30 times.

To prevent vertical transmission of HBV, the first phase of vaccination is carried out immediately after birth (no later than 24 hours), then vaccination is carried out after 1, 2 and 12 months. For this purpose, combined passive-active immunization of newborns from mothers with hepatitis B or virus carriers can be used. Specific immunoglobulin is administered immediately after birth, and vaccination is carried out in the first 2 days. Vaccination is carried out in a regimen of 0, 1, 2 months with revaccination at 12 months. Such passive-active immunization reduces the risk of infection of a child in mothers with HBeAg from 90 to 5%.

Widespread introduction of vaccination against hepatitis B will reduce the incidence of not only acute but also chronic hepatitis B, as well as cirrhosis and primary liver cancer.