Ausencia de circulación de poliovirus en departamentos colombianos con coberturas vacunales inferiores a 80% / Absence of poliovirus circulation in Colombian departaments with vaccination coverage below 80%

El presente estudio se propuso explorar la posible circulación silente de poliovirus salvajes y derivados de la vacuna (VDPV, por sus siglas en inglés), en departamentos de Colombia con cobertura de vacunación para polio (OPV, por sus siglas en inglés) menor de 80%. Se colectaron 52 muestras de aguas residuales que se concentraron mediante precipitación con polietilenglicol y cloruro de sodio. La detección viral se realizó mediante aislamiento y la identificación por neutralización del efecto citopático, así como mediante reacción en cadena de la polimerasa convencional y en tiempo real, posterior a la transcripción reversa (TR-RCP y rTR-RCP). Los poliovirus aislados se caracterizaron por secuenciación del gen VP1. En dos de las 52 muestras hubo presencia de poliovirus Sabin 2 con más de 99% de similitud de secuencia con la cepa OPV Sabin 2. Se detectó circulación de enterovirus no polio en 17,3% de las muestras. Los serotipos identificados correspondieron a coxsackievirus B1, echovirus 30 y echovirus 11. No se detectaron evidencias de circulación de VDPV ni poliovirus salvaje en los departamentos de Colombia con coberturas de OPV inferiores a 80%.

This study aims to explore a possible silent circulation of wild and vaccine-derived polioviruses in departments of Colombia with polio vaccination coverage of below 80%. The study collected 52 samples of wastewater concentrated as a result of precipitation with polyethylene glycol and sodium chloride. The viral detection was carried out through isolation and the identification through neutralization of the cytopathic effect, as well as through a conventional polymerase chain reaction following reverse transcription. The isolated polioviruses were characterized by the VP1 gene sequence. In two of the 52 samples, there was a presence of the Sabin type 2 poliovirus with more than 99% sequence similarity with the Sabin type 2 strain polio. Circulation of the nonpolio enterovirus was detected in 17.3% of the samples. The serotypes identified corresponded to coxsackievirus B1, echovirus 30, and echovirus 11. No evidence of the spread of either vaccine-derived poliovirus or wild poliovirus was detected in the departments of Colombia with polio coverage lower than 80%

Immunogenicity study for tetra and penta component vaccines in infants

A randomized controlled trial to evaluate the immunogenicity of combined Hemophilus Influenzae type b with DTP +/- injectable polio vaccine and the immunogenicity of giving one injectable polio vaccine combined with the first of 3 doses of oral polio vaccine. After parental consent, infants were randomized into 4 groups to receive the following vaccines; First group: Single Hemophilus Influenzae type b vaccine [PRP-T, Act-HIB[registered] in addition to DPT and oral polio vaccine. Second group: Combined [PRP-T+DTP] TETRAct-HIB[registered] and oral polio vaccine. Third group: First dose is combined [PRP-T+DPT+injectable polio vaccine] PENTAct-HIB[registered] and oral polio vaccine. Then, the 2nd and 3rd dose is TETRAct-HIB[registered] and oral polio vaccine. Fourth group: DPT and oral polio vaccine only [Control group]. Vaccines were given at 6 weeks, 3 months and 5 months. Blood samples were collected from all children, one month after the 3rd dose at the age of 6 months. Samples were sent for laboratory assay for anti-PRP, Diphtheria anti-toxin, Tetanus anti-toxin, polio antibody type 1, 2 and 3 and pertussis Agglutinins. Single Hemophilus Influenzae type b vaccine produced a higher anti-PRP level [15 ug ml[-1]] compared to combined Hemophilus Influenzae type b vaccine, [9.5 ug ml[-1]] in the second group and [11 ug ml[-1]] in the 3rd group but without significant level. It was found that 90% of non-vaccinated children in our sample are lacking the protective level against Hemophilus Influenzae type b diseases. Giving injectable polio vaccine with oral polio vaccine in the first of 3 doses did not affect the level of polio antibody for the 3 poliovirus types but positivity after the 3 polio doses increased compared to previous studies. In the 4 groups, 100% of the children achieved the protective level against Pertussis, Tetanus and 95% for Diphtheria. No significant negative interaction was found between vaccine antigens used in the study. Combined vaccines are effective methods to include Hemophilus Influenzae type b and injectable polio vaccine in the Extended Program of Immunization without unacceptable decrease in immunogenicity of each component

Poliomyelitis: immune status of the populotion of Kuwait

A comprehensive program to immunize children against polioviruses was started in Kuwait in 1976. This report is the first laboratory study aimed at investigating the immune status of the population of Kuwait to polioviruses. By using a virus neutralization procedure, the prevalence and the titer of poliovirus-specific antibodies were determined in 759 serum samples. Samples represented the following age groups: 0-1 months, 1-9 years, 10-19 years, 20-29 years, 30-39 years and 40-60 years. The first two age groups, during which the polio vaccinations are given, were studied in detail. Results allow for the following conclusions: [1] Monovalent [type 1] polio vaccine, given at birth, has an impact on the early development of immunity. It prevents the drop in the [maternal] antibody level during the first 2 months of life. [2] Immunity to all three types of polioviruses reaches a high level at the age of 5-6 months. [3] Both the prevalence and the level of antibody remain high in older age groups. The data reported here prove that the use of trivalent oral polio vaccine along with an efficient vaccination coverage has led to the complete elimination of paralytic poliomyelitis in Kuwait. Maintaining the polio-free status requires laboratory monitoring of the antibody level and nature of circulating poliovirus strains