关键词： Oral poliovirus vaccines   Mass immunization   Poliovirus   Dosage   Immune response   Poliomyelitis   Rainy seasons   Polio   Immunity  

摘要： To compare the immunogenicity of routine versus mass campaign doses of oral poliovirus vaccine (OPV), serum neutralizing antibodies were measured in 254 children before and after two mass vaccination campaigns in Jordan. Precampaign seroprevalences to poliovirus types 1, 2, and 3 in children who had received three, four, or five routine doses of OPV were compared with postcampaign seroprevalences in children who had received one, two, or three routine doses plus two mass campaign doses. Seroprevalences were consistently higher in subgroups that received two doses through mass campaigns than in subgroups that received all doses through the routine program, especially for poliovirus type 3. Geometric mean titers were also consistently higher for mass campaign subgroups, particularly for poliovirus type 3. The findings suggest that adding further doses of OPV to the routine schedule is unlikely to have as great an impact on the immune state of children as administering the same number of doses during mass campaigns.

关键词： poliovirus   replicon   C-fragment tetanus toxin   protection   vaccine vector   immune response  

摘要： In this study, we describe the construction of poliovirus genomes or ''replicons'' which contain the C fragment gene of tetanus toxin substituted for the poliovirus P1 capsid Upon transfection of replicon RNA into cells, we immunoprecipitated a protein corresponding to the C-fragment of tetanus toxin using tetanus-specific antibodies. Using a recombinant vaccinia virus expressing poliovirus P1 capsid protein (VV-P1) to provide P1 protein, the replicon RNA was encapsidated;stocks of the replicons were generated by passage with VV-P1. The immunogenicity of the replicons was determined by immunization of transgenic mice which are susceptible to poliovirus. A serum antibody response to poliovirus and tetanus toroid was detected in all of the immunized mice. Protection against a lethal dose of tetanus toxin generally correlated with the levels of serum anti-tetanus antibodies. To address whether pre-existing antibodies to poliovirus limit the effectiveness of the replicon as a vaccine vector, mice were first immunized with the inactivated poliovirus vaccine followed by immunization with the replicons expressing C-fragment protein. Anti-tetanus antibodies were detected in these mice after a single administration of the replicon;these antibodies conferred protection upon challenge with tetanus toxin. These results demonstrate the potential use of poliovirus replicons encoding foreign proteins to induce a protective antibody response, even in the presence of pre-existing antibodies to poliovirus. (C) 1997 Published by Elsevier Science Ltd.

关键词： Oral poliovirus vaccines   Inactivated poliovirus vaccines   Poliovirus   Antibodies   Dosage   Poliomyelitis   Immunization schedules   Excretion  

摘要： The relative immunity induced by sequential administration of inactivated poliovirus vaccine (IPV) produced in human diploid cells and live attenuated oral poliovirus vaccine (OPV) was evaluated by randomization of 510 infants to receive IPV and OPV sequentially according to one of three experimental schedules, IPV only, or OPV only. The antibody response to two IPV doses was lower than expected. However, for each of the IPV-OPV sequential schedules, the first OPV dose significantly enhanced seroconversion rates and geometric mean microneutralization antibody titers. Three months after the final dose, 96%-99%, 99%-100%, and 81%-100% of infants had antibodies to poliovirus types 1, 2, and 3, respectively, and subjects with two or more prior OPV doses were significantly less likely than those with none or one prior OPV dose to excrete virus in feces after an OPV challenge. Sequential IPV-OPV immunization is now recommended for routine use in the United States. The optimal schedule consists of two IPV doses followed by two OPV doses.

关键词： Antigens   Response rates   Oral poliovirus vaccines   Dose response relationship   Enzyme linked immunosorbent assay   Poliovirus   Infections   Monoclonal antibodies  

摘要： Monoclone-based IgM capture ELISAs were developed for each of the three poliovirus serotypes and compared with a neutralization assay for detecting response to trivalent oral poliovirus vaccine among 224 infants. The IgM-based response rates were significantly higher than the neutralizing antibody-based rates: 958 versus 83% to poliovirus type 1, 99% versus 94% to poliovirus type 2, and 89% versus 59% to poliovirus type 3. IgM responses to the first vaccine dose were significantly associated between serotypes, suggesting that some of the discordance may reflect a heterotypic IgM response. When the response rates in 4 vaccine formulation groups were compared, group differences using the two assays were similar for poliovirus types I and 2 but not for type 3. Therefore, IgM results using these assays may not be adequate substitutes for neutralizing antibody results when determining vaccine response.

关键词： Oral poliovirus vaccines   Hepatitis B vaccines   Poliovirus   Poliomyelitis   Inactivated poliovirus vaccines   Diptheria pertussis tetanus vaccines   Measles vaccines   Health care administration   Toxoid vaccines  

摘要： To determine the feasibility of a vaccination strategy that would reduce the risk of vaccine-associated paralysis while retaining a barrier against the spread of wild poliovirus, a 2-year project was undertaken using enhanced-potency inactivated poliovirus vaccine (IPV) administered at 2 and 3 months of age followed by doses of both IPV and oral poliovirus Vaccine (OPV) administered at 4 and 9 months of age, Vaccination coverage by 12 months of age with three or more doses of IPV and two doses of OPV among 16,566 infants eligible for vaccination was >95% and >80%, respectively. Among 51 children from whom blood samples were obtained 45 days after their third dose of IPV and first dose of OPV, 100% had serum neutralizing antibodies (reciprocal titer greater than or equal to 10) to all three poliovirus types. No cases of paralytic poliomyelitis due to either wild or vaccine-related strains were reported. The project demonstrated the feasibility, safety, and high immunogenicity of sequential use of IPV followed by OPV in Romania.

关键词： Poliovirus   Surveillance   Infections   Specimens   Health surveillance   Estimators   Population policy   Population estimates   Polio  

摘要： A basic framework for describing sensitivity of surveillance to detect poliovirus is extended from individuals to general populations (population sensitivity). Using the mathematical formulations for population sensitivity, the theoretical behavior of surveillance sensitivity under various conditions is analyzed. As a region nears the elimination of poliovirus, population sensitivity falls to a value lower than the case-to-infection ratio, regardless of the system proficiency. Also, a second stool specimen makes a substantial contribution to population sensitivity only in regions with relatively low specimen sensitivity and then only over a narrow range of population infection incidence. Estimates of the mean numbers of infected and uninfected acute flaccid paralysis cases investigated in a season are derived. These may serve as additional indicators of system operation but require the collection of 2 specimens per case.

关键词： Oral poliovirus vaccines   Poliovirus   Seroepidemiologic studies   Inactivated poliovirus vaccines   Birth   Dosage   Antibodies   Placebos  

摘要： Seroprevalence and geometric mean titers (GMTs) were compared at 6 and 10 months after vaccination with monovalent type 1 oral poliovirus vaccine (OPV) at 6 months and trivalent OPV at 7 and 9 months. Group 1 had received 4 doses of OPV, group 2 OPV at birth and 3 doses of OPV and inactivated poliovirus vaccine (IPV), and group 3 placebo at birth and 3 doses of IPV, A total of 547 infants completed the study, At 10 months, seroprevalence to poliovirus type 1 was 98%, 99%, and 98% in groups 1, 2, and 3;100%, 100%, and 98% to poliovirus type 2;and 80%, 96%, and 91% to poliovirus type 3, Differences in seroprevalence among the groups were significant for poliovirus type 3 (P <.001), Between 6 and 10 months, significant increases in seroprevalence and GMTs occurred for poliovirus type 1 but not for types 2 and 3, Two OPV doses following 3 IPV doses did not significantly increase seroprevalence or raise GMTs for poliovirus types 2 and 3;however, significant increases were found for poliovirus type 1, which may have benefitted from monovalent type I administration.

摘要： In 1989, a localized outbreak of 10 cases of poliomyelitis occurred in Saudi Arabia. Wild poliovirus type 1 was isolated from 5 patients. To determine the patterns of poliovirus circulation, partial nucleotide sequences of the poliovirus isolates were compared. These isolates were remarkably diverse. Two isolates were closely related to each other and to viruses isolated during the 1988 epidemic in Oman. Two other isolates were very similar to viruses found in Egypt, The fifth isolate was distantly related to the latter pair. The molecular data suggest that the 10 cases represented three separate outbreaks. The virologic findings underscore the potential for Saudi Arabia, which receives millions of guest workers and their families each year from countries in which polio is endemic, to be exposed to frequent importations of wild polioviruses. To restrict the circulation of imported polioviruses, Saudi Arabia must maintain high population immunity to poliovirus in all geopolitical divisions.

摘要： In May 1985, the Pan American Health Organization launched an initiative to interrupt indigenous transmission of the wild poliovirus from the Western Hemisphere by the year 1990. The strategy to achieve this goal was based on the maintenance of high levels of immunity in the population at risk and the establishment of a surveillance system to detect polio cases and respond promptly with control measures. On 23 August 1991, a 2-year-old boy with acute flaccid paralysis due to wild poliovirus was detected in Junin, Peru, the last isolation of such a virus in the entire Western Hemisphere. In 1990, an International Commission for the Certification of Eradication of Poliomyelitis Eradication (ICCPE) was established by the Pan American Health Organization to eventually determine if transmission was interrupted. After 3 years of follow-up and review of surveillance data, the ICCPE declared that wild poliovirus transmission had been interrupted in the Americas.

关键词： Polio   Poliovirus vaccines   Virology   Specimens   Health surveillance   Poliomyelitis   Training   Countries   Antiserum   Labor standards  

摘要： A network of virologic laboratories has been established by the World Health Organization to conduct surveillance for wild poliovirus and to provide evidence for the certification of poliomyelitis eradication. The network consists of >60 national laboratories isolating and identifying polioviruses within countries;16 regional reference laboratories, providing intratypic differentiation of wild and vaccine strains and assisting with quality assurance and training;and 6 global specialized laboratories, conducting research, preparing reference reagents, and providing genomic sequencing of wild polioviruses, advanced training, and expert virologic advice. Laboratories collaborate with national eradication programs in the detection, reporting, clinical investigation, and virologic testing of stool specimens obtained in connection with cases of acute flaccid paralysis and, where indicated, from healthy children and the environment. A quality assurance system, leading to World Health Organization accreditation, involves training in standardized techniques, use of centrally prepared typing antisera, annual proficiency testing and follow-up action, and monitoring of standard performance indicators.