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AIM: To reveal features of rubella epidemic process during start of mass immunization and to determine rubella virus genotypes circulating in Saint-Petersburg. MATERIALS AND METHODS: Official data on rubella morbidity during 1995-2007 and number of vaccinated against rubella children and adults were used in this study. During 2006-2008 males aged 17-20 years with rubella diagnosis were eligible for laboratory test on rubella. Nasopharyngeal swabs and blood specimenswere tested by PCR and virus isolation on cell culture (PK13). Genotyping of isolates was performed on the basis of 600 nucleotide sequence of E1 gene from 8731 to 9653 n.p. RESULTS: It was shown that mass vaccination of children and young women against rubella during 4 years resulted in 3-fold drop of rubella incidence inwhole population, which diminishes the probability of infection in pregnant women and born of children with congenital rubella syndrome. In age structure of rubella morbidity the proportion of children aged 3-6 and 7-14 years decreased by 1.5-fold. Epidemic process loss the features of autoregulating system (periodicity and seasonal incidence peaks). Results of genotyping showed that isolates belonged to genotype 1E. High degree of homology (97.7-99.6%) to isolates from Barnaul and Belorussia was demonstrated. CONCLUSION: Issues on isolates' origin and success of measures on elimination of endemic rubella could be resolved by further studies on isolation and genotyping of rubella virus strains in Saint-Petersburg and North-East region of Russian Federation in the whole.

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Investigation of hepatitis A (HA) outbreak developed in 2005 among workers of food stores networkwas performed using conventional epidemiologic diagnostics as well as methods of molecular epidemiology. In 14 of 15 ill persons, using polymerase chain reaction, HAV RNA was detected by PCR in serum obtained on 2 - 25 day of illness (mean - 9.3 days). In 10 cases it was possible to determine nucleotide sequence of VP1/VP2 region of HAV genome and perform phylogenetic analysis of obtained isolates. It was determined that all isolates belonged to subgenotype IA, had high degree of homology and grouped in one cluster. These findings demonstrate their descendance from one source of infection, which, with high degree of probability, was the cook who made salads from fresh vegetables. HAV strain, which caused this epidemic outbreak circulates in Saint Petersburg for a long time and was already detected in 2004. Importance of vaccination against HA for persons working in manufacturing and distribution of food and use of molecular epidemiologic methods of surveillance for this infection is underlined.

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This study investigated the causes of invasive bacterial infections in children aged <15 years in St Petersburg, Russia, during 2001-2003, using culture and antigen detection methods (rapid antigen latex agglutination (RAL)) for normally sterile body fluids. A pathogen was detected in 90 cases (culture 50, RAL 40). Neisseria meningitidis was the most common pathogen (66%), followed by Haemophilus influenzae (19%) and Streptococcus pneumoniae (16%). Meningitis was the main clinical diagnosis (68/90, 76%), with N. meningitidis serogroup B, H. influenzae type b (Hib), and S. pneumoniae serogroup 1 being the most common isolates. Hib was less prevalent in St Petersburg than it was in industrialised countries before the introduction of Hib vaccinations.

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During three seasons at the period of 1992-1996 immunization of elderly persons, living in homes for old people, against influenza with inactivated influenza vaccine (IIV) was carried out. Altogether 856 persons were immunized intranasally, 581 persons constituting the control group. For comparison, 4,825 healthy young adults aged 18-24 years were immunized under similar conditions. The study revealed that the intranasal immunization of elderly persons with IIV, made in two administrations, was safe and stimulated sufficient humoral and secretory immunity: the level of seroconversions was 24.3-41.0% to type A(H1N1) influenza virus, 29.6-50.7% to type A(H3N2) influenza virus, 39.3-59.6% to type B influenza virus; the level of diagnostic IgA conversions was 31-38%. Immunization produced a pronounced prophylactic effect (the effectiveness index 1.6-1.7), as well as decreased the total mortality level by half. The tactics of the immunization of persons from high risk groups against influenza in medical practice is discussed.

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