[POSSIBILITY OF INFLUENZA PANDEMIC PREDICTION].

Five influenza pandemics emerged in the 20th and 21st centuries. Data regarding possibility of infection of swine with human influenza viruses-and persistent circulation of these strains among swine with subsequent infection of humans with these viruses were obtained in the recent years. A possibility of prediction of influenza pandemics by constant observation and study of influenza viruses circulating among swine is discussed in the paper.

Chitosan as an adjuvant for poliovaccine.

The use of inactivated poliomyelitis vaccine is very important for eradicating poliomyelitis. However, this vaccine is not available readily in underdeveloped countries due to the high cost. Adjuvants can improve the immunogenicity of a vaccine and reduce the antigen dose required for vaccination, thus lowering the cost of the vaccine.

Evaluation of properties of chitosan as an adjuvant for inactivated influenza vaccines administered parenterally.

Studies on mice showed that chitosan as an adjuvant for H5 inactivated influenza vaccines administered intramuscularly enhances significantly antibody titers and protective efficiency not only against homologous influenza viruses, but also against drift variants. Chitosan adjuvanted vaccines induced high antibody titers after a single immunization and with a low dose of antigen. High antibody titers remained for at least 6 months.

Chitosan as an adjuvant for parenterally administered inactivated influenza vaccines.

The addition of 0.5% of a chitosan derivative to inactivated influenza vaccines injected parenterally resulted in a four or six to tenfold increase in antibody titres after a single-dose or two-dose intramuscular immunization of mice, respectively, in comparison with antibody titres after immunization without chitosan. Chitosan-adjuvanted vaccines enhanced antibody titers against drift variants of A- and B-type human influenza viruses four to six times compared with the vaccines without chitosan.

The effect of mass influenza immunization in children on the morbidity of the unvaccinated elderly.

The objectives of these studies were to analyse the effect of mass influenza immunization in children on the morbidity of unvaccinated non-institutionalized elderly during an influenza epidemic. A mass vaccination campaign with vaccine was conducted in children aged 3-6 years attending kindergartens (57.4% of 6374) and aged 7-17 years attending schools (72% of 34237) in two communities of the Moscow region.

Development of cell culture (MDCK) live cold-adapted (CA) attenuated influenza vaccine.

Optimal conditions are determined for growing cold-adapted reassortant strains of a live influenza vaccine in MDCK cell line cultivated in a fermenter with a serum-free medium and microcarriers. The studied MDCK cell line meet all national and WHO requirements for the finite cell lines used for the production of biological preparations. CA reassortant vaccine strains grown in such conditions which fully preserve its mutations and the mutations lead to amino acid substitution in all genome segments of the studied CA reassortants.

Influenza vaccines: a main problem in control of pandemics.

The optimal strategy for control of pandemic influenza is early vaccination with influenza vaccine produced from influenza pandemic strains. However, for pandemic control, vaccine improvements are essential and should include quicker ways of manufacturing and testing of vaccine as well as flexibility on the part of licensing bodies. The production of mass doses of monovalent vaccine in a short time can be more realistic if egg independent production technology can be adopted.

Introduction to pandemic influenza through history.

For the past 400 years, epidemics resembling influenza have been recorded in many countries. Epidemics from as early as the 16th Century in England and the 18th Century in the USA are recognizable as influenza, even in the absences of precise knowledge of their causative agents.

Interrupting the transmission of wild polioviruses with vaccines: immunological considerations.

In 1988 the World Health Assembly set the goal of global poliomyelitis eradication by the year 2000. Substantial progress has been made, and 143 countries reported no poliomyelitis cases associated with the wild virus in 1993. This article reviews the immunological considerations relevant to interrupting the transmission of wild polioviruses with vaccines.

WHO recommendation on potential use of new poliomyelitis vaccines.

Due to the intensive use of Sabin attenuated oral poliomyelitis vaccine, the incidence of poliomyelitis is continuing to decline, particularly in the Americas and Western Europe. In some developing countries, the use of trivalent attenuated vaccine may, however, sometimes produce sub-optimal antibody responses. Moreover, rare cases of vaccine-associated paralytical poliomyelitis could become increasingly prevalent, especially in countries that achieve control of the wild-type polioviruses.

Influenza--its impact and control.

Influenza is an underestimated public health problem. Epidemics spread rapidly from country to country and may affect as many as 500 million people across the world in a moderate influenza year. The disease, particularly influenza A, kills and the new influenza viruses which appeared in 1957 (Asian influenza) and 1968 (Hong Kong) are estimated to have caused at least 100,000 deaths in the United States of America.

Vaccine preventable viral diseases in developing countries.

There are several viral infectious diseases with a high impact on developing countries which can be prevented by immunization with existing vaccines. The most important are poliomyelitis, measles, hepatitis B and yellow fever. Vaccines against poliomyelitis and measles used within the framework of the WHO/Expanded Programme on Immunization prevent about 1.

Influenza surveillance.

The main objectives of influenza surveillance are: collection of influenza virus isolates and analysis of their antigenic characteristics so that the most appropriate virus variants can be recommended as constituents of influenza vaccines for use during the next epidemiological season; collection and analysis of information on influenza morbidity and mortality; and earliest possible detection of influenza epidemics. Exact estimates of the specific morbidity and mortality due to influenza are now being carried out in only certain countries. Simple notification of clinical cases and deaths without laboratory confirmation is unsatisfactory and leads to errors in interpretation.

Genome and antigenic analysis of influenza A (H3N2) viruses isolated from an epidemic in a closed community of Carmelite nuns.

Eighteen influenza A (H3N2) viruses were isolated during a single outbreak in a closed community of Carmelite nuns. Serological analysis of the virus haemagglutinin (HAs), using a panel of monoclonal antibodies, demonstrated antigenic microheterogeneity. In contrast, no significant biochemical differences were detected in viral genes by RNA:RNA hybridisation or in structural or nonstructural polypeptides analysed by high-resolution polyacrylamide gel electrophoresis (PAGE) or by limited proteolysis followed by PAGE.

The immune response to influenza vaccines.

Specific immunity to influenza is associated with a systemic immune response (serum haemagglutination inhibition antibody), local respiratory immune response (virus-specific local IgA and IgG antibodies in nasal wash), and with the cell-mediated immune response. Both inactivated and live influenza vaccines induce virus-specific serum antibody which can protect against infection with influenza virus possessing the same antigenic specificity. In the absence of serum antibodies, local antibodies in nasal wash are a major determinant of resistance to infection with influenza virus.

WHO strategy for the global elimination of new cases of hepatitis B.

Hepatitis B infection and its sequelae remain major public health problems internationally despite the existence of sensitive tests to screen blood and blood products for hepatitis B surface antigen (HBsAg) and immunogenic vaccines. Since the human hepatitis B virus has no known animal reservoir, a systematic vaccination programme against hepatitis B, including vaccination of all newborns and young children within the framework of the WHO Expanded Programme on Immunization, as well as protection of high-risk individuals, together with the testing of all blood and blood products for HBsAg, could eliminate hepatitis B virus infection and its sequelae. However, for the successful realization of this programme, many important and difficult problems need to be solved, especially those related to vaccination strategy, determination of the duration of immunity, investigation of the mechanisms of perinatal and horizontal virus transmission, and improvement of the immunogenicity of hepatitis B vaccine.

Perinatal transmission of hepatitis B virus in high-incidence countries.

Hepatitis B is a serious public health problem throughout the world. Hepatitis B virus (HBV) induces acute hepatitis with a case-fatality rate of about 1%. Even more important, 5-10% of patients infected with HBV become chronic carries and about 25% of these will die due to cirrhosis and hepatocellular carcinoma.

Haemagglutinin of influenza A virus is a target for the antiviral effect of Norakin.

The anticholinergic anti-parkinsonism drug Norakin is an inhibitor of influenza virus multiplication. By crossing a Norakin-resistant variant of fowl plague virus (FPV) strain Weybridge with the sensitive FPV/Rostock/34 wild-type virus, Norakin-resistant recombinants were obtained. Analyses of the gene composition showed that all Norakin-resistant recombinants had inherited their haemagglutinin gene from the Norakin-resistant parent strain.

Variation of influenza A (H3N2) viruses isolated in the G.D.R. during 1969-1980 epidemics.

A collection of 39 influenza A virus strains of the subtype H3N2 isolated in G.D.R.

Comparative studies of H3N2 influenza virus strains isolated in May-June, 1982, and in the subsequent epidemic in February, 1983: antigenic and genome analysis.

Comparative studies have been undertaken on the H3N2 influenza virus strains isolated in Leningrad in May-June, 1982 and those isolated in the subsequent winter epidemic in February, 1983. Analysis of the isolates with ferret antisera against standard influenza viruses of the H3N2 subtype and with monoclonal antibodies against A/Bangkok/1/79 virus revealed a considerable but similar degree of heterogeneity in the HA antigenic specificity of the strains isolated in the spring-summer, 1982, as in the winter, 1983, periods and also a close resemblance between the antigenic specificities of the strains of these two epidemics. However comparative genome analysis of the strains using cRNA:vRNA hybridization technique revealed that in terms of the gene homology, the influenza virus strains which circulated in the spring-summer period of 1982 resembled the strains responsible for the previous rather than subsequent epidemic.