Safety and immunogenicity of conventional subunit and MF59-adjuvanted influenza vaccines in human immunodeficiency virus-1-seropositive patients.

In this study of influenza vaccination, 37 human immunodeficiency virus (HIV)-1-seropositive patients were randomized to receive either a vaccine with a conventional subunit or one adjuvanted with MF59. Blood samples were collected at the time of vaccination, and then 30 and 180 days later, to evaluate immunogenicity, CD4+ T-lymphocyte count and HIV-1 RNA levels. Seroconversion rates against the three viral strains included in the vaccine ranged between 44% and 72% and 53% and 68% for the adjuvanted vaccine and the subunit vaccine, respectively. Other criteria of the European Medicines Evaluation Agency were also met. Vaccination was not associated with serious adverse events. Local and systemic effects were mild and of short duration. CD4+ T-lymphocyte counts and viraemia levels were not negatively affected by vaccination. These results confirmed the safety and immunogenicity of these currently available vaccines in HIV-1-seropositive patients, thus supporting the recommendation for influenza immunization in this high-risk category.

Feasibility of vaccination in preventing secondary cases of hepatitis A virus infection.

Although the secondary transmission of hepatitis A virus (HAV) infection is preventable through vaccination, it is not known whether the vaccination of household contacts is feasible. To this end, we conducted a prospective cohort study among the household contacts, 40 years of age or less, of all persons infected with primary HAV infection (index cases) and admitted to eight hospitals in southern Italy within 7 days of onset. Household contacts were vaccinated, and serum samples were taken at vaccination and after 14 and 45 days. Secondary cases were defined as those with IgM seroconversion occurring at least two weeks after enrollment. Coprimary cases were those assumed to have had the same exposure as the index case. Susceptible cases were those who were negative for both IgG and IgM. A total of 495 household contacts participated (acceptance rate of 65%); 65% were vaccinated within 4 days of admission of the index case and 95% within 7 days. At enrollment, 196 (39.6%) household contacts were immune (IgG-positive serum). During follow-up, 19 (3.8%) were IgM-positive: 13 (2.6%) were coprimary cases and 6 (1.2%; 95% CI: 0.2-3.2) secondary cases (5 identified at 14 days from vaccination and 1 at 45 days). Of the 241 susceptible cases, 192 (79.7%) had developed IgG antibodies at 14 days and only 3 (1.2%) did not develop IgG antibodies at 45 days. The 65% acceptance rate and the finding that 95% of the participating household contacts were vaccinated within 7 days of the index case's hospitalization indicate that timely vaccination is indeed feasible. The necessity of returning for the collection of blood samples probably decreased the acceptance rate.

Drug resistance testing in PBMCs of HIV infected patients.

HIV infected patients are considered a sort of reservoir having different genetically distinct viral variants (quasispecies), that evolve from the starting virus inoculum. Frequently, during replication, HIV can generate nucleotide differences in the new viral population; such genetic changes may be uninfluential in viral "fitness" (replication capacity) or give the virus some advantages under a selective pressure, due to immune response or drug treatment. The use of potent combination therapy for the treatment of HIV infections has certainly improved the "quality of life" for patients, decreasing the viral load in the plasma (HIV RNA). In our study, we investigated whether detection of drug resistance-related mutations was possible in circulating PBMCs, which represent a sort of genetic archive of viral drug resistances, when the levels of viral RNA were reduced to below 400 or 50 copies/ml, since, generally, plasma samples with more than 1,000 copies/ml of HIV RNA are needed to generate some results. The study was successfully performed sequencing proviral HIV DNA in PBMCs from 32 samples belonging to 25 patients, using a new modified protocol, that showed a good reproduciblity and very interesting data, also in patients with low or without circulating HIV RNA levels.