La influenza es una enfermedad de de medio mi116n en Estados Unidos. En caracteristicas epidemiologicas muy partiChile, en el mismo periodo, se atribuyen a culares entre las cuales destaca su tendencia esta causa 36.115 defunciones. Estas cifras a producir grandes pandemias que se prodemuestran que el impacto producido por pagan a traves de paises y de continentes, la pandemia de influenza fue muy superior afectando en algunas oportunidades a una al de la guerra misma, afectando a la importante proporcion de la poblacion del humanidad no ~610 por sus graves tasas de

The justification to this special issue about WHO are given, underlining the international impact of its policies and programmes in the last 50 years.

Bacterial meningitis is a problem for Public Health that has to be reviewed periodically. Most of the infections are due to Meningococcus, Haemophilus influenzae or Streptococcus pneumoniae Seventy per cent of the cases are seen in children less than 5 years old; mortality ranges between 5% to 20% of the patients. Progress has been made with vaccination for Meningococcus types A and C and for H influenzae type B. In Chile, meningococcal meningitis is endemic, with epidemic bouts in the north part of the country. Currently, studies are in progress in Santiago with vaccination againt H influenzae type B, in the hope that it can be extended to the rest of the country.

1052 prelevements seriques ont ete etudies. L'antigene a ete trouve 0,62% parmi 477 medecins, infirmieres et auxiliaires techniques de laboratoire. 248 diabetiques et 36 cirrhotiques ne presentaient pas d'Ag HBs. 1 seul cas etait positif parmi 291 malades d'ulcere peptique ou de colon irritable. 261 sujets presentaient des anticorps (23 parmi 110 professionnels, 36 parmi 133 diabetiques et aucun parmi 18 cas de cirrhose hepatique alcoolique)

Summary Adult persons developed substantial antibody increases against essentially all pneumococcal capsular types following injection of polyvalent pneumococcal vaccine containing 50 μg of each capsular polysaccharide per dose. Revaccination 13 months after the previous immunization did not evoke important further increases in antibodies and there was substantially greater local reaction at the injection site than when the previous dose was given. This finding appeared due to local reaction of antigens with circulating antibodies in the area of injection, since there was a correlation between the measured amount of circulating pneumococcal antibodies and the degree of reaction. Infants less than 2 years of age who were given a half-dose of vaccine generally responded poorly when compared with adults. In studies of 3- to 5-month-old infants, there was some increase _in antibodies when a booster dose of vaccine was given 6 months after the first. Very high level antibody responses against all capsular types were obtained when revaccination was delayed until 2 years of age.

The bifurcated needle vaccination method used successfully against smallpox is a relatively simple technique that can be administered by personnel with only basic preparation and a minimum of training. This fact suggests that it could prove useful in campaigns of BCG vaccination against tuberculosis--especially for vaccination of newborns. With this end in mind, two studies were carried out in Santiago, Chile, to examine previously reported difficulties with the method and to assess its potential as an alternative to the best current method, that of intradermal inoculation. These studies indicated that previously reported variations in the results achieved by different vaccinators could be markedly reduced. However, they also found that the bifurcated needle method did not cause a sufficiently large dose of vaccine to enter the subject--even when fifteen needle strokes and a highly concentrated vaccine (160 mg per ml) were employed. It was thus concluded that although modification of the needle or other changes might ultimately yield satisfactory results, the bifurcated needle technique cannot yet be recommended for BCG vaccination of newborns.

This is a second report of epidemiological and clinical investigation, related to the arsenic health problem, unique in the world, occurring in the city of Antofagasta, Chile. The arsenic problem originates in the chronic contamination of water supply in the city during 12 years. This phenomena, investigated clinically and epidemiologically and first reported in 1971, prompted the installation of a water treatment plant. This report aims to evaluate the working efficiency of the plant. The study was carried out through the examination of arsenic content in hair and nail clipping samples of the inhabitants of Antofagasta and the determination of this element in cultivated vegetables and carbonated beverages. Also a clinical study in school children, looking for cutaneous lesions attributed to arsenicism, was made. Results are encouraging. They reveal that contamination persists but in significantly lower levels.