[Persistence of hepatitis A virus antibodies after primary immunization and response to revaccination in children and adolescents with perinatal HIV exposure]

Abstract

OBJECTIVE:: To assess possible factors associated with the loss of antibodies to hepatitis A 7 years after the primary immunization in children of HIV-infected mothers and the response to revaccination in patients seronegative for hepatitis A.

METHODS:: Quantification of HAV antibodies by electrochemiluminescence was performed in 39 adolescents followed up at the Pediatric Aids Clinic of Federal University of São Paulo (Unifesp): 29 HIV-infected (HIV group) (median age: 12.8 years) and 10 HIV-exposed but non-infected (ENI group) (median age: 13.4 years). All of them received two doses of HAV vaccine (Havrix^(r)) in 2002.

RESULTS:: The median age at primary immunization (PI) was 5.4 years for HIV group and 6.5 years for ENI group. All children, from both groups, had antibodies to HAV >20 mIU/mL after PI. Seven years later, the ENI group showed a median concentration of antibodies = 253.5 mIU/mL, while the HIV group = 113.0 mIU/mL (Mann-Whitney test, p=0.085). All ENI group and 23/29 (79.3%) from HIV group mantained HAV antibodies 7 years after PI. The levels of hepatitis A antibodies in the primary vaccination were the only factor independently associated with maintaining these antibodies for 7 years. The group that lost HAV seropositivity was revaccinated and 83.3% (5/6) responded with antibodies >20 mUI/mL.

CONCLUSIONS:: The antibodies levels acquired in the primary vaccination in the HIV group were the main factor associated with antibodies loss after HAV immunization.

Keywords: Adolescent and children; Crianças e adolescentes; HIV; Hepatitis A vaccine; Immunossupression; Imunossupressão; Vacina de hepatite A.

Figure 1.. Hepatitis A Antibodies in HIV Group and ENI Group 30 days and 7 years after primary immunization.

Figure 2.. Dynamics of plasma levels of hepatitis A antibodies after revaccination in 6 patients from the HIV group without protective antibody levels seven years after primary immunization. Note: the sample from child #6 immediately before the 2nd booster dose was lost.

Figure 3.. Evolution of viral load at four different moments: 30 days after primary vaccination (PV), seven years after PV, immediately before the 1st and 2nd booster dose (REVAC) in 6 patients from the HIV group who did not respond to revaccination.

Figure 4.. CD4+ T cell count evolution at four different time: 30 days after primary vaccination (PV), 7 years after PV, immediately before the 1st and 2nd booster doses (REVAC) in 6 patients from the HIV group who did not respond to revaccination.

Figura 1.. Anticorpos contra hepatite A no Grupo HIV e no Grupo ENI 30 dias e sete anos após imunização primária.

Figura 2.. Dinâmica dos níveis plasmáticos dos anticorpos contra hepatite A após a revacinação nos seis pacientes do grupo HIV sem níveis protetores de anticorpos sete anos após a imunização primária. Observação: a amostra da criança 6 imediatamente antes da 2ª dose de revacinação foi perdida.

Figura 3.. Evolução da carga viral, em quatro momentos: 30 dias após vacinação primária (VP), sete anos após VP, imediatamente antes da 1a e da 2a doses da revacinação (revac) nos seis pacientes do grupo HIV que não responderam à revacinação.

Figura 4.. Evolução da contagem de células T CD4+ em quatro momentos: 30 dias após vacinação primária (VP), sete anos após VP, imediatamente antes da 1a e da 2a doses da revacinação (revac) nos seis pacientes do grupo HIV que não responderam à revacinação.