To evaluate a) the safety and immunogenicity of anti-HAV-inactivated vaccine administered during the first year of life to anti-HAV seronegative babies, and b) the antibody persistence in a low/intermediate endemic area.
After having obtained informed written consent from mothers, 92 babies were vaccinated at 4 and 10 mo of age. All babies were seronegative at birth and did not present HAV-RNA shedding in three serial stool samples taken at 1, 2 and 3 mo of age.
No general side effects (fever > 38 degrees C) were observed. After the first dose of vaccine, 70/82 (85.4%) babies developed anti-HAV > 10 mIU/ml and 36/82 (43.9%) > 20 mIU/ml. After the second dose of vaccine, all babies developed a titre > 20 mIU/ml, and GMT was 877 mIU/ml. After 1 y of follow-up, the decreasing rate was similar to that reported for adult populations. Furthermore, three babies doubled the titre observed 1 mo after the second dose, indicating the possible spread of HAV even in a low/intermediate endemic area.
Anti-HAV vaccine is safe, immunogenic and able to induce immune memory, and can be integrated into the routine infant immunization schedule during the first year of life.
"The most important feature of the vaccine is the appearance of neutralizing antibodies to HAV, which can be measured by ELISA and the virus titer is expressed in terms of ELISA units (ELU). Studies showed that a 0.5 ml intramuscular dose of a vaccine prepared from the HM-175 strain of HAV containing 720 ELU of hepatitis A antigen had a seroconversion rate of 44% in infants (De et al. 2006), 100% in children (Findor et al. 1996) and 88–100% in adults (Andre et al. 1992; Clemens et al. 1995; Davidson et al. 1992; Goubau et al. 1992; Westblom et al. 1994), after 1 month of inoculation. Experiments with other doses showed that seroconversion rates after 1 month inoculation of the vaccine containing 360 ELU of hepatitis A antigen was 95% in children (Clemens et al. 1995) and 85–93% in adults (Goubau et al. 1992). "
[Show abstract][Hide abstract] ABSTRACT: Viruses are a significant cause of morbidity and mortality around the world. Determining the minimum dose of virus particles
that can initiate infection, termed the minimum infective dose (MID), is important for the development of risk assessment
models in the fields of food and water treatment and the implementation of appropriate infection control strategies in healthcare
settings. Both respiratory and enteric viruses can be shed at high titers from infected individuals even when the infection
is asymptomatic. Presence of pre-existing antibodies has been shown to affect the infectious dose and to be protective against
reinfection for many, but not all viruses. Most respiratory viruses appear to be as infective in humans as in tissue culture.
Doses of <1 TCID50 of influenza virus, rhinovirus, and adenovirus were reported to infect 50% of the tested population. Similarly, low doses
of the enteric viruses, norovirus, rotavirus, echovirus, poliovirus, and hepatitis A virus, caused infection in at least some
of the volunteers tested. A number of factors may influence viruses’ infectivity in experimentally infected human volunteers.
These include host and pathogen factors as well as the experimental methodology. As a result, the reported infective doses
of human viruses have to be interpreted with caution.
KeywordsMinimum infectious dose–Respiratory viruses–Enteric viruses–Infection
[Show abstract][Hide abstract] ABSTRACT: Although early vaccination is recommended in candidates for solid organ transplantation (SOT), consensual protocols do not yet exist. We applied an SOT vaccination protocol in the Hospital Clinic of Barcelona (Spain). Serology was performed before and after vaccination and compliance with the vaccination schedule was analysed during the period 2003-2004. Two hundred and thirty seven patients (72.9% male; mean age 56.31 years, range 19-72) were included. A total of 74.5% of subjects susceptible to hepatitis B virus infection responded to hepatitis B vaccination. Most patients were protected against hepatitis A, varicella, measles, rubella and mumps. The vaccine protocol was implemented satisfactorily and the administration of two courses of hepatitis B vaccine was shown to be effective.
[Show abstract][Hide abstract] ABSTRACT: Breastmilk specimens from three women with acute hepatitis A virus (HAV) infection were studied. Anti-HAV immunoglobulin M and immunoglobulin G antibodies were detected in serum and breastmilk specimens of the three women. The three women also had serum HAV RNA. However, HAV RNA was detected only in two of the three breastmilk specimens. It is interesting that none of the three infants contracted clinical HAV infection. Furthermore, mothers with HAV infection should not be encouraged to discontinue breastfeeding.
Breastfeeding Medicine 04/2012; 7(4):313-5. DOI:10.1089/bfm.2011.0084 · 1.25 Impact Factor
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