Epidemiology of pneumonia in the pre-pneumococcal conjugate vaccine era in children 2-59 months of age, in Ulaanbaatar, Mongolia, 2015-2016.

BACKGROUND: Respiratory diseases, including pneumonia, are the second largest cause of under-five mortality in Mongolia and the most common cause of childhood hospitalization. However information regarding the contribution of Streptococcus pneumoniae to pneumonia causation in Mongolia is limited. We aimed to describe the epidemiology of hospitalized children aged 2-59 months with pneumonia, enrolled into a surveillance program in the period prior to pneumococcal conjugate vaccine (PCV) introduction, in Mongolia. METHODS: An expanded pneumonia surveillance program enrolled children, who met the surveillance case definition, at participating hospitals, between April 2015 and May 2016. Cumulative incidence rates were calculated by district for all pneumonia endpoints using district specific denominators from the Mongolian Health Department census for 2016. Socio-economic and disease-associated factors were compared between districts using chi-squared tests. RESULTS: A total of 4318 eligible children with pneumonia were enrolled over the 14 month period. Overall the incidence for all-cause pneumonia in children aged 12-59 months was 31.8 per 1000 population; children aged 2-11 months had an almost four-fold higher incidence than children aged 12-59 months. Differences were found between districts with regards to housing type, fuel used for cooking, hospital admission practices and the proportions of severe and primary endpoint pneumonia. DISCUSSION: This study shows a high burden of pneumonia in children aged 2-59 months in Mongolia prior to PCV introduction. Rates differed somewhat by district and age group and were influenced by a number of socio-economic factors. It will be important to consider these differences and risk factors when assessing the impact of PCV introduction.

Puesta al día en vacunación antineumocócica en adultos / Update on pneumococcal vaccination in adults

La enfermedad invasiva por Streptococcus pneumoniae constituye una importante causa de morbilidad y mortalidad, y es la primera causa de muerte prevenible mediante vacunación en el mundo, no solo en niños sino en todas las edades. Tanto la vacuna polisacárida como la vacuna conjugada antineumocócicas han demostrado reducción de las tasas de enfermedad invasiva en adultos. En los últimos años, a la luz de nueva evidencia disponible, los esquemas de vacunación antineumocócica para esta población han sufrido modificaciones. Este documento ofrece una actualización sobre las recomendaciones de vacunación a través de los fundamentos que han llevado a dicho cambio. (AU)

The Streptococcus pneumoniae invasive disease is a major cause of morbidity and mortality, being the leading cause of vaccine-preventable death in the world, not only in children but in all ages. Both the polysaccharide vaccine and pneumococcal conjugate vaccine have shown reduced rates of invasive disease in adults. In recent years, in light of new evidence available, schedules of pneumococcal vaccination for this population have changed. This document provides an update on vaccine recommendations through the rational that have led to this change. (AU)

Vacunación antineumocócica polisacárida 23-Valente / No disponible

No disponible

A century of pneumococcal vaccination research in humans.

Sir Almroth Wright coordinated the first trial of a whole-cell pneumococcal vaccine in South Africa from 1911 to 1912. Wright started a chain of events that delivered pneumococcal vaccines of increasing clinical and public-health value, as medicine advanced from a vague understanding of the germ theory of disease to today's rational vaccine design. Early whole-cell pneumococcal vaccines mimicked early typhoid vaccines, as early pneumococcal antisera mimicked the first diphtheria antitoxins. Pneumococcal typing systems developed by Franz Neufeld and others led to serotype-specific whole-cell vaccines. Pivotally, Alphonse Dochez and Oswald Avery isolated pneumococcal capsular polysaccharides in 1916-17. Serial refinements permitted Colin MacLeod and Michael Heidelberger to conduct a 1944-45 clinical trial of quadrivalent pneumococcal polysaccharide vaccine (PPV), demonstrating a high degree of efficacy in soldiers against pneumococcal pneumonia. Two hexavalent PPVs were licensed in 1947, but were little used as clinicians preferred therapy with new antibiotics, rather than pneumococcal disease prevention. Robert Austrian's recognition of high pneumococcal case-fatality rates, even with antibiotic therapy, led to additional trials in South Africa, the USA and Papua New Guinea, with 14-valent and 23-valent PPVs licensed in 1977 and 1983 for adults and older children. Conjugation of polysaccharides to proteins led to several pneumococcal conjugate vaccines licensed since 2000, enabling immunization of infants and young children and resultant herd protection for all ages. Today, emergence of disease caused by pneumococcal serotypes not included in various vaccine formulations fuels research into conserved proteins or other means to maximize protection against more than 90 known pneumococcal serotypes.

Pneumococcal vaccines for children: a global public health priority.

Pneumococcal conjugated vaccines have been recommended in children for over a decade in many countries worldwide. Here we review the development of pneumococcal vaccines with a focus on the two types currently available for children and their safety record. We discuss also the effect of vaccines, including the 13-valent pneumococcal conjugate vaccine, on invasive pneumococcal diseases in children, particularly bacteraemia, pneumonia and meningitis, as well as on mucosal disease and carriage. In regions where immunization was implemented in young children, the number of invasive pneumococcal diseases decreased significantly, not only in the target age group, but also in younger and much older subjects. Challenges and future perspectives regarding the development of new 'universal' vaccines, which could bypass the current problem of serotype-specific protection in a context of serotype replacement, are also discussed.

Pneumonia research in Papua New Guinea: 1967-1986.

Between 1967 and 1985 research on pneumonia in Papua New Guinea (PNG) was fundamental not only to standard treatments of disease in PNG, but also to the establishment of the World Health Organization's global Program for Control of Acute Respiratory Infections. Pneumonia was the leading cause of death in both population-based and hospital studies. Research that began in 1967 revealed a pattern of disease in adults reminiscent of that seen in industrialized countries in the early 20th century. Streptococcus pneumoniae (pneumococcus) was the predominant causative organism. Pneumococci were commensals of the upper respiratory tract that invaded first the lungs and then the blood stream. Some serotypes were more invasive than others and case fatality increased with deeper levels of invasion. The pandemic of Hong Kong (H3N2) influenza spread to the Southern Highlands in 1969 resulting in 2000 deaths. The conclusion that pneumococcal pneumonia had been the principal cause of death led to the establishment of a pneumonia research unit in Tari. A field trial of pneumococcal polysaccharide vaccine showed the vaccine to be most effective in preventing invasive disease. Vaccination reduced pneumonia mortality by 44% in previously healthy adults. The epidemiological situation was more complex in children than in adults because many different species and serotypes of bacteria could be isolated from lung aspirate. Although many of these organisms would normally have been regarded as non-pathogenic, S. pneumoniae and Haemophilus influenzae, recognized pathogens, were the principal causes of severe morbidity and mortality. The same principles of carriage of and invasion by upper respiratory commensals applied as much to children as they did to adults, and the rank order of invasive serotypes of S. pneumoniae and H. influenzae was the same in different age groups. Slow maturation of a child's immune system meant, however, that children could be susceptible to invasion by particular serotypes. Infants were frequently colonized by pathogenic bacteria within days of birth. Nasal discharge, which was extremely common, was most probably a result of domestic smoke pollution and low standards of hygiene. Aspiration of infected secretions was a likely explanation for the variety of organisms isolated from lung aspirate. A trial of pneumococcal polysaccharide vaccine showed the vaccine to be effective in preventing death from pneumonia in children 6-9 months of age provided pneumonia was not associated with other causes of death; this result was shown to be consistent with the principles of infection and invasion described above. Principles of antibiotic therapy for child pneumonia were also established at this time.

Changing interest among physicians toward pneumococcal vaccination throughout the twentieth century.

Interest in using pneumococcal vaccination among physicians has come full circle since the early twentieth century. Interest first arose during an epidemic among South African gold miners when a potential therapeutic agent, ethylhydrocupreine, caused significant toxicities. When a safe and effective vaccine became available in 1946, interest in using it paradoxically waned as its introduction coincided with the advent of penicillin. Physicians believed that this effective new antibiotic would change pneumonia from a dreaded infection to a casual, infrequent occurrence. The manufacturer was unable to promote vaccine use and withdrew it from the market. Enthusiasm for vaccination remained low long after limitations in antibiotic therapy of pneumococcal infections became clear in the 1960s and a new vaccine once again became available in 1978. Interest in vaccination was eventually renewed in the 1990s when the propagation of pneumococcal resistance to multiple agents diminished the complete confidence that physicians had in antibiotics and when populations at risk for infection were expanding. Scientific evidence of vaccine efficacy, demonstrated in 1944 and 1977, has not alone been sufficient to convince physicians to use vaccination. Rather, doctors have accepted the need to vaccinate for pneumococcus when they have recognized the shortcomings of therapeutic measures during epidemic periods.

Pneumococcal otitis media and pneumococcal vaccines, a historical perspective.

Although pneumococcal otitis media was recognized in the 19th century, the illness stimulated little interest in prophylaxis until recently. Whole cell vaccines of killed pneumococci, developed to prevent pneumonia, were replaced by vaccines of capsular polysaccharides following demonstration of their antigenicity in adults. Failure of the latter to stimulate antibodies in infants and young children and demonstration of the efficacy of capsular polysaccharide-protein conjugate vaccines in preventing infection with Hemophilus influenzae type b has led to the development of polyvalent pneumococcal polysaccharide-protein conjugate vaccines. Preliminary studies have shown them to be highly effective in preventing invasive pneumococcal disease in the first 2 years of life, and studies of their impact on otitis media are currently in progress.