Serological Evaluation of Varicella and Hepatitis A Vaccines Using Injector Delivery

- Children of both genders older than 13 months and younger than 30 months of age.

- Available for follow-up for at least 45 days at public day care centers funded by São Paulo City local government.

- Written informed consent signed by parents or legal guardians after reading and explanation

- Suspect/verified diagnosis of congenital or acquired immunodeficiency syndrome (AIDS)

- Suspect/verified diagnosis of malign neoplasia

- Children on treatment with high-dose systemic corticosteroids (equivalent to prednisone 2 mg/kg/day, for two or more weeks), or immunosuppressive therapy.

- Received a vaccine with live attenuated strain of virus within less than 30 days

- Suspect/verified diagnosis of chickenpox or has already been immunized against chickenpox (varicella).

- Suspect/verified diagnosis of hypersensibility to any ingredient of the vaccine.

- One of the parents or legal guardians of the minor does not agree with the study.

- Any other circumstances that may potentially damage the minor or prevent procedures from being carried out according to evaluation of the research team.

- Child shows signs or symptoms of an active intercurrent disease (e.g. fever, rash, etc.) that may interfere with the evaluation of adverse events after immunization at the research team's discretion. In this case, the participant may be reevaluated within the following three months in order to verify eligibility.