Hanna Nohynek

The World Health Organization's (WHO) case definition for childhood pneumonia, composed of simple clinical signs of cough, difficult breathing and fast breathing, is widely used in resource poor settings to guide management of acute respiratory infections. The definition is also commonly used as an entry criteria or endpoint in different intervention and disease burden studies.

A recent study in The Lancet reported on the effectiveness against invasive pneumococcal disease of the only pneumococcal conjugate vaccine currently available in routine American healthcare settings

An 11-valent pneumococcal conjugate vaccine could provide significantly larger reduction in pneumococcal disease burden than the currently available 7-valent vaccine formulation in many countries. In total, 50 infants were enrolled to this open, uncontrolled study, which evaluated the safety and immunogenicity of an aluminium adjuvanted 11-valent mixed-carrier diphtheria toxoid or tetanus protein-conjugated vaccine (11-PncTD) when administered in three doses at 6, 10 and 14 weeks of age simultaneously with DTwP//PRP-T and OPV vaccines in Filipino infants. The rates of local reactions between the two injection sites, those associated with the 11-PncTD vaccine and those with the DTwP//PRP-T were almost of equal frequency for all three vaccine doses except for induration, which was significantly more common in the DTP//PRP-T injection site. Fever was present in 39%, 22% and 21% of infants following each of the three doses. Antibody responses were determined by an enzyme immunoassay method before the first vaccination and after the three doses. The vaccine elicited a significant anti-pneumococcal polysaccharide antibody response against all serotypes included in the vaccine, except for type 14, for which the pre-vaccination geometric mean antibody concentration (GMC) was high (1.61 microg/ml). The GMCs one month after the vaccination series ranged from 1.1 micrograms/ml for type 6B to 23.4 microg/ml for type 4. The 11-PncTD vaccine is safe, well-tolerated and immunogenic. The effectiveness of the non-adjuvanted formulation of the vaccine in preventing pneumonia is currently being evaluated in the Philippines.

Pregnant women in developing countries are vaccinated with tetanus toxoid (TT) to prevent neonatal tetanus. In populations in which the maternal TT-vaccination program is efficiently implemented, responses of the infant to TT and TT-conjugated vaccines such as Haemophilus influenzae type b (Hib) capsular polysaccaride (PS) TT-conjugate (Hib-TT) vaccine may be depressed. To study the influence of transplacentally acquired anti-TT antibodies on responses to TT vaccination and to Hib-TT vaccine. One hundred ninety-four healthy Filipino infants received three doses of a Hib conjugate (either Hib-TT, PRP-OMP or HbOC) with diphtheria-tetanus-pertussis vaccine (DTP) given simultaneously but in a separate syringe at the age of 6, 10 and 14 weeks (primary series). In addition 54 of the study children received a booster dose of Hib-TT at 9 months simultaneously with the measles vaccine. Transplacentally acquired anti-TT did not interfere with the anti-Hib PS antibody (anti-Hib PS) response to any of the conjugates. The transplacentally acquired anti-TT was not significantly associated with the concentration of anti-Hib PS either before or after the booster dose of Hib-TT. High concentrations (≥1 IU/ml) of transplacentally acquired anti-TT inhibited the infants' anti-TT responses. High concentration of transplacentally acquired anti-TT did not depress anti-Hib PS responses to the Hib-TT vaccine. On the other hand the high anti-TT concentrations somewhat depressed the anti-TT responses of the infants. However, the anti-TT concentrations attained were in the protective range in all study children after either the primary series (DTP + Hib-TT) or the booster dose of Hib-TT.

• Objective: To determine the etiologic agents in children with acute lower respiratory infection. Design: A survey of a series of patients. Setting: General pediatric hospital serving an urban population with and without referrals in Helsinki, Finland. Participants: 135 Finnish children aged 2 months to 15 years (mean, 1.75 years), with clinically defined acute lower respiratory infection (with difficulty of breathing), or found to ave fever and a pneumonic infiltrate on chest roentgenogram. Selection Procedures: Consecutive sample on voluntary basis. Interventions: None. Main Results: Of 121 children with adequate samples, an etiologic diagnosis could be established in 84 (70%): 30 (25%) had bacterial, 30 (25%) viral, and 24 (20%) mixed infections. Antibody assays alone identified the agent in 91% of positive cases. Conclusions: Bacterial infections are common but generally underestimated in acute lower respiratory infection; serologic methods add significantly to their detection. (AJDC. 1991;145:618-622)