Tag: Pneumonia

Acute Respiratory Infections: Haemophilus influenzae VaccineHaemophilus influenzae Vaccine
Haemophilus influenzae is the second most common cause of bacterial pneumonia in children. Vaccine against H influenzae type b is widely used and effective against invasive infection in children over 2 years of age. However, a high proportion of H influenzae infections, especially in developing countries, are due to other serotypes and nonencapsulated strains for which no vaccine currently exists. Moreover, like the pneumococcal vaccine, the Haemophilus capsular polysaccharide vaccine is not effective in very young children. Capsular polysaccharide pneumococcal and H influenzae vaccines conjugated to a protein carrier appear to elicit higher antibody responses in young children than nonconjugated vaccines, and trials of the efficacy of such vaccines are in progress. However, the cost of conjugate vaccines may prohibit their widespread use, at least until evidence of their value generates demand for their large-scale production. …Read the rest of this article

Respiratory Syncytial (RS) Virus and Other Respiratory Virus Vaccines
The RS virus is the most common cause of bronchiolitis in infants worldwide. It is associated with significant mortality and possible damage to bronchioles, with residual abnormalities of function. An effective vaccine could be expected to have a significant impact on incidence and mortality from ARI in infants and prevent associated longterm damage. Attempts to prepare vaccine against RSV by traditional methods were not successful—indeed, inactivated RSV vaccine had the effect of exacerbating subsequent natural disease, rather than conferring protection. Recent molecular research has shown that the viral envelope proteins are immunologically the most important components, and vaccines prepared from them may be available for trial in the next few years. Prospects for vaccines for other respiratory viruses still seem to be remote. …Read the rest of this article

Acute Respiratory Infections: Rertussis VaccineRertussis Vaccine
Current whole cell vaccine is generally highly effective in protecting susceptible children against whooping cough after household exposure. However, concern about the safety of the vaccine has led to poor rates of administration in many countries. Acellular pertussis vaccines that include only those purified and toxoided antigens thought to be necessary to stimulate protective antibodies, have recently been developed. Trials have shown these to evoke as good antibody responses and fewer local and mild systemic reactions than whole cell vaccines, but efficacy trials have proved disappointing. Further work is needed to evaluate different component vaccines before they can be recommended routinely.
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ARI in Adults
There are 3 ways in which ARI might influence the development of chronic airways disease in adults: (1) By initiating the onset. There is no reliable evidence to support this suggestion. (2) By speeding progression of established disease. Fletcher and Peto argued on the basis of a follow-up of 30-59-year-old men in West London that ARI has no permanent effect on mucous hypersecretion or lung function. However, the length of follow-up may have been too short for permanent changes to have become apparent. There are few other studies that enable any firmer conclusions. (3) By causing or contributing to mortality in those with CAD. Influenza epidemics have been associated with excess respiratory mortality, and it is possible that other respiratory viral infections may similarly affect mortality rates. further …Read the rest of this article

Acute Respiratory Infections: Risk Factors for ARIRisk Factors for ARI
There is considerable evidence that social and environmental factors have a major influence on the incidence and severity of childhood respiratory infections. Most of the evidence comes from studies on populations of children in developed countries. What evidence there is from studies in developing countries suggests that the same factors operate. Low birth weight and malnutrition are of great importance in influencing the incidence and mortality from ARI. Other factors include overcrowding, number and age of other siblings, sharing a bedroom, parental cigarette smoking, and outdoor and domestic air pollution. These factors appear to have a greater influence in infants than in older children. …Read the rest of this article

Agents of ARI
A large number of microbial agents can cause ARI (Table 4). The most common primary agents are viruses and the most lethal are bacteria, often as secondary invaders. Agents that affect the bronchi and bronchioles tend to be associated with long-term abnormalities more than those that cause pneumonia. It is difficult, however, to obtain quantitative information about the relative frequency of different pathogens by diagnostic categories or pathology. …Read the rest of this article

Acute Respiratory Infections: ARI in Children Childhood Antecedents of Adult CADThe first involves the continued follow-up of the 1946 British Birth Cohort to age 36 years. Previous studies at ages 20 and 25 had suggested an association between childhood chest illness and respiratory symptoms in adult life. At 36, when peak expiratory flow rate (PEFR) was measured as well as respiratory symptoms (MRC Bronchitis Questionnaire), after allowing for smoking habit, an independent association was found between low PEFR, respiratory symptoms, and lower respiratory tract infection before age 10 (Table 3). Thus, in this cohort, there is evidence of a persisting association between childhood respiratory experience and adult respiratory symptoms and low PEFR. Various social and environmental factors in childhood were also investigated for associations with adult respiratory experience. Of these, crowding at age 2 years was significantly associated with mean PEFR and respiratory symptoms at 36 years. further
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