Specific prophylaxis of influenza with inactivated split vaccine Vaxigrip

Influenza remains a serious health problem, annually causing epidemics embracing up to 10% of the population of the world, and at the periods of pandemics this number may rise 4- to 6-fold. In the overwhelming majority of the countries the prophylaxis of influenza is carried out at present out with the use of inactivated vaccines. One of such vaccines is the highly purified split vaccine Vaxigrip (Aventis-Pasteur, France), permitted for use in Russia since 1992. The article contains the review of the data of literature, as well as the materials provided by the authors, which indicate that the preparation has low reactogenicity (also for children starting from the age of 6 months) and high reactogenic properties, leading to antibody formation at protective levels with respect to all three components of the vaccine. The vaccine has been found to ensure pronounced prophylactic efficacy for 70-90% of vaccinees and a decrease in influenza morbidity even in case of using the preparation a week before the onset of the epidemic. This shows the advantage of Vaxigrip in comparison with other inactivated vaccines.     

痢疾菌苗研究进展

痢疾是全世界范围内流行的肠道传染病。随着分子生物学技术的发展,迄今已构建了新一代预防痢疾的疫苗,其中包括:具有侵袭力和不具侵袭力的单价口服活菌苗候选株;它们与大肠杆菌、伤寒沙门氏菌和血清型不同的痢疾杆菌组成的双价和三价菌苗候选株;以及以脂多糖和核糖体为基础的不经胃肠的组分菌。猴体和人体试验证明它们安全有效。预计在未来的10年中,将会有一个或几个安全有效的痢疾疫苗投放市场。     

Specific prophylaxis of influenza in organized groups of children with the vaccine Vaxigrip

The results of the open comparative study on epidemiological effectiveness and tolerance of the vaccine Vaxigrip, carried out in 109 children aged 2-15 years with different initial state of health, are presented. The index of epidemiological effectiveness of Vaxigrip was 4.09 (p < 0.05), the rate of epidemiological effectiveness--75.6% (p < 0.05). Vaxigrip was found to be well tolerated by both healthy children and those with different functional disturbances and chronic diseases. The study revealed that the use of Vaxigrip was not accompanied by any systemic postvaccinal reactions. High prophylactic effectiveness and good tolerance of Vaxigrip make it possible to recommend it for mass immunoprophylaxis of influenza in children.     

To shigellosis epidemicity in East-Slovakian region

A set of 2227 strains of Shigella sonnei isolated from dysentery patients in East-Slovakian region from 1975 through 1977 was analyzed by age and sex of patients, place and time of isolation, and by phage type, colicin type and antibiogram patterns of strains. The study showed that some phage types tended to occur in association with certain colicin types, the most common combination being that of phage type 75 and col factór Ei (86% of strains). In 1976 and 1977 this phage type gradually replaced col factor Ia that in 1975 was predominant. The rise in the incidence of these strains was striking and pointed to their intensive circulation among the population of East-Slovakian districts, particularly among children of preschool age. A hypothetic assumption is that such changes in the phage type and colicin type patterns might precede the new epidemic wave of dysentery outbreaks in the population. That would also explain e.g. the irregularity of dysentery epidemic cycles encountered in Czechoslovakia during the decade from 1972 through 1982. The analysis of strains by pattern of antibiogram showed that the percentage of strains resistant to all antimicrobials and sulphonamides tested remained virtually constant over the three years under study and did not exceed 6% of strains. Only the strains monoresistant to tetracycline were found to show a striking rise in their incidence from 5% in 1975 to 23% in 1977. In the majority of cases they were S. sonnei strains with col factor Ei.     

A protective factor of ribosomal shigellosis vaccine

Shigella ribosomal vaccine was shown previously to possess protective properties in the keratoconjunctival test on guinea pigs and to be capable of preventing experimental infection in 90% of challenged monkeys. The presence of the O-specific component (OSC) constituting about 0.5% of the ribosomal preparation by serological activity suggested its importance for the protective effect. This was studied in experiments with two O-specific immunosorbents prepared by coupling anti-O rabbit antibodies with Staphylococcus aureus cells or with CNBr-Sepharose. Ribosomes treated with immunosorbents proved to be lacking the serologically active OSC and lost their ability to induce O-antibody response in rabbits and mice. After the removal of this component ribosomal preparations were incapable of ensuring protection from Shigella kerato-conjunctival infection. The isolated OSC was also inactive in this test. The data obtained in this investigation confirm the hypothesis stating that the protective activity of Shigella ribosomal vaccine is based on the combined action of ribosomes and O-specific factor whose nature and properties require further study.     

Moose soup shigellosis in Alaska.

Following a community gathering held in early September 1991, an outbreak of gastroenteritis occurred in Galena, Alaska. We conducted an epidemiologic investigation to determine the cause of the outbreak. A case of gastroenteritis was defined as diarrhea or at least 2 other symptoms of gastrointestinal illness occurring in a Galena resident within a week of the gathering. Control subjects included asymptomatic residents who either resided with an affected person or were contacted by us during a telephone survey. Of 25 case-patients, 23 had attended the gathering compared with 33 of 58 controls. Among persons who attended the gathering and from whom we obtained a food consumption history, 17 of 19 case-patients and 11 of 22 controls ate moose soup. No other foods served at the gathering were associated with illness. Ten case-patients had culture-confirmed Shigella sonnei. Many pots of moose soup were served each day, and persons attended the gathering and ate moose soup on more than 1 day. Moose soup was prepared in private homes, allowed to cool, and usually served the same day. We identified 5 women who had prepared soup for the gathering and in whose homes at least 1 person had a gastrointestinal illness occur at the time of or shortly before soup preparation. This investigation suggests that eating contaminated moose soup at a community gathering led to an outbreak of shigellosis and highlights the risk of eating improperly prepared or stored foods at public gatherings.     

Assay of IgA to Shigella flexneri during shigellosis

Abstract An enzyme-linked immunosorbent assay (ELISA) to Shigella flexneri 2a whole bacterium was used to determine IgM, IgG and IgA serum titers in 50 acute-phase shigellosis patients and 37 controls, i.e., hospital patients without known recent infections. Compared to controls, the shigellosis patients displayed statistically raised average serum titers to S. flexneri in all 3 above immunoglobulin classes, most notably IgA, which displayed an average 42-fold increase. Specific IgM and IgG were 5- and 16-fold higher, respectively. All sera displayed statistically raised titers in at least one immunoglobulin class. A Widal agglutination detected a 7-fold increase in serum titers; this was comparable to the IgM ELISA. Statistical analysis showed that the intra-assay error of the ELISA varied from 5 to 14%, depending on the absorbance from which titers were calculated. A second ELISA was performed on the above shigellosis sera to determine titers to purified lipopolysaccharide (LPS): a statistical correlation was found between these and the above values for all 3 immunoglobulin classes. We conclude that the use of S. flexneri whole bacterium as an antigen in an IgA ELISA is a statistically valid and convenient parameter for monitoring shigellosis, comparable to the use of LPS as antigen, and more sensitive than IgM or IgG ELISAs or agglutinations.     

Development of a new guinea-pig model of shigellosis

Shigellosis is a major form of bacillary dysentery caused by Shigella spp. To date, there is no suitable animal model to evaluate the protective efficacy of vaccine candidates against this pathogen. Here, we describe a successful experimental shigellosis in the guinea-pig model, which has shown the characteristic features of human shigellosis. This model yielded reproducible results without any preparatory treatment besides cecal ligation. In this study, guinea-pigs were discretely infected with virulent Shigella dysenteriae type 1 and Shigella flexneri type 2a into the cecocolic junction after ligation of the distal cecum. All the experimental animals lost ～10% of their body weight and developed typical dysentery within 24-h postinfection. In the histological analysis, distal colon showed edema, hemorrhage, exudation and inflammatory infiltrations in the lamina propria. Orally immunized animals with heat-killed S. dysenteriae type 1 and S. flexneri type 2a strains showed high levels of serum immunoglobulin G (IgG) and mucosal IgA antibodies and conferred significant homologous protective immunity against subsequent challenges with the live strains. The direct administration of shigellae into the cecocolic junction induces acute inflammation, making this animal model useful for assessing shigellosis and evaluating the protective immunity of Shigella vaccine candidates.     

The cyclicity and prognosis of shigellosis morbidity in Russia

The epidemic process (EP) of shigellosis morbidity proceeds in cycles. As shown in this study, cyclic curves are the sum of polyharmonic fluctuations, being the axis of EP. The duration of one cycle is 18 years, and its configuration is stably retained for a long time. In Nizhny Novgorod shigellosis morbidity is strongly correlated with air temperature is summer at the peak of cyclic rises and moderately correlated in the years of low morbidity. In some cities of the Russian Federation fluctuations of air temperature have been found of occur synchronously with disturbances of the magnetic field of the earth. The character and stability of EP cycles provide grounds for the prognostication of shigellosis morbidity. The current cycle will end in the year 2000, and then natural preconditions for a new cyclic rise will appear.