Intestinal Immunity to Poliovirus Following Sequential Trivalent Inactivated Polio Vaccine/Bivalent Oral Polio Vaccine and Trivalent Inactivated Polio Vaccine-only Immunization Schedules: Analysis of an Open-label, Randomized, Controlled Trial in Chilean Infants.

Background: Identifying polio vaccine regimens that can elicit robust intestinal mucosal immunity and interrupt viral transmission is a key priority of the polio endgame. Methods: In a 2013 Chilean clinical trial (NCT01841671) of trivalent inactivated polio vaccine (IPV) and bivalent oral polio vaccine (bOPV; targeting types 1 and 3), infants were randomized to receive IPV-bOPV-bOPV, IPV-IPV-bOPV, or IPV-IPV-IPV at 8, 16, and 24 weeks of age and challenged with monovalent oral polio vaccine type 2 (mOPV2) at 28 weeks. Using fecal samples collected from 152 participants, we investigated the extent to which IPV-bOPV and IPV-only immunization schedules induced intestinal neutralizing activity and immunoglobulin A against polio types 1 and 2. Results: Overall, 37% of infants in the IPV-bOPV groups and 26% in the IPV-only arm had detectable type 2-specific stool neutralization after the primary vaccine series. In contrast, 1 challenge dose of mOPV2 induced brisk intestinal immune responses in all vaccine groups, and significant rises in type 2-specific stool neutralization titers (P < .0001) and immunoglobulin A concentrations (P < 0.0001) were measured 2 weeks after the challenge. In subsidiary analyses, duration of breastfeeding also appeared to be associated with the magnitude of polio-specific mucosal immune parameters measured in infant fecal samples. Conclusions: Taken together, these results underscore the concept that mucosal and systemic immune responses to polio are separate in their induction, functionality, and potential impacts on transmission and, specifically, provide evidence that primary vaccine regimens lacking homologous live vaccine components are likely to induce only modest, type-specific intestinal immunity

Impacto de la investigación infectológica en la salud y el bienestar del ser humano

La prolongación de la vida, así como el avance en su calidad, acaecido de manera formidable durante las últimas décadas se debe en gran parte al control de las enfermedades infecciosas. Este control se ha logrado en buena parte gracias al progreso de la investigación biomédica, a estas alturas más que centenaria, fruto del esfuerzo de miles de investigadores que han aportado sus “granos de arena”, generando una sumatoria de nuevo conocimiento. En determinadas ocasiones el conocimiento generado permite una especie de “salto cuántico” o “breakthroughs” con un impacto rápido y evidente en la disminución de la mortalidad y/o morbilidad. Esta es una revisión no sistemática basada en la reflexión personal, con los sesgos que esta conlleva, sobre los hitos en la investigación infectológica reciente que han impactado en la salud humana y lo que podría esperarse en el futuro cercano. Al final se incluye literatura recomendada que profundiza varios de los tópicos presentados

A third gyrovirus species in human faeces

Until 2011 the genus Gyrovirus in the family Circoviridae consisted of a single virus (Chicken anemia virus or CAV) causing a common immunosuppressive disease in chickens when a second gyrovirus (HGyV) was reported on the skin of 4% of healthy humans. HGyV is very closely related to a recently described chicken gyrovirus, AGV2, suggesting that they belong to the same viral species. During a viral metagenomic analysis of 100 human faeces from children with diarrhoea in Chile we identified multiple known human pathogens (adenoviruses, enteroviruses, astroviruses, sapoviruses, noroviruses, parechoviruses and rotaviruses) and a novel gyrovirus species we named GyV3 sharing &lt;63% similarity with other gyrovirus proteins with evidence of recombination with CAV in its UTR. Gyroviridae consensus PCR revealed a high prevalence of CAV DNA in diarrhoea and normal faeces from Chilean children and faeces of USA cats and dogs, which may reflect consumption of CAV-infected/vaccinated chickens. Whethe

Outbreaks of acute gastroenteritis in Antofagasta Region. Chile 2010 Brote de gastroenteritis aguda en la Región de Antofagasta, Chile. 2010

Outbreaks of acute gastroenteritis are a public health problem. Norovirus is known as the most common cause (50%). In Chile, immediate notification allows surveillance of these events. We describe an acute gastroenteritis outbreak that occurred in Antofagasta region, between March and April 2010. An observational study was conducted to perform the outbreak investigation. Local residents who met case definition were included. Stool samples, epidemiological surveys and environmental samples were requested. The outbreak began approximately on March 8, 2010 and lasted until April 28 with 31,036 reported cases (rate 54 per 1000 inhabitants). The most affected age group was between 25 and 44 years, and diarrhea was the main symptom (97% of cases). We determined the presence of norovirus genogroup II in clinical and environmental samples. This outbreak was caused by consumption of raw vegetables from La Chimba, which were watered and contaminated with treated sewage containing low concentrat