Vaccination against measles. II. Clinical trial in Nigerian children

Synthesis of Evidence to Characterize National Measles and Rubella Exposure and Immunization Histories

Population immunity depends on the dynamic levels of immunization coverage that countries achieve over time and any transmission of viruses that occur within the population that induce immunity. In the context of developing a dynamic transmission model for measles and rubella to support analyses of future immunization policy options, we assessed the model inputs required to reproduce past behavior and to provide some confidence about model performance at the national level. We reviewed the data available from the World Health Organization (WHO) and existing measles and rubella literature for evidence of historical reported routine and supplemental immunization activities and reported cases and outbreaks. We constructed model input profiles for 180 WHO member states and three other areas to support disease transmission model development and calibration. The profiles demonstrate the significant variability in immunization strategies used historically by regions and member states and the epidemiological implications of these historical choices. The profiles provide a historical perspective on measles and rubella immunization globally at the national level, and they may help immunization program managers identify existing immunity and/or knowledge gaps.

The clinical reaction of Nigerian children to measles vaccine with and without gamma globulin

1. The severity of measles in infants and young children in Ilesha in Nigeria suggested this as a suitable centre for a trial of measles vaccine.

2. The trial was divided into three stages. In the first the vaccine was given to a group of 26 children who could be kept under close observation and were seen twice daily. In the second the vaccine was given to 120 children, a similar group receiving gamma globulin and an inert material. In the third stage the effect of vaccine and gamma globulin given as separate injections to 378 children, was compared with that of gamma globulin and inert material given to another control group. The second and third stages were run on the ‘double blind’ principle.

3. The children receiving vaccine alone showed fairly severe reactions but none were disabled by them; for example, 19 % had fever over 103° F. The reactions were similar to those observed in American children, with the one exception that diarrhoea was seen amongst African children receiving vaccine without gamma globulin. Those receiving vaccine and gamma globulin had only minor reactions. In the vaccinated children there was a notable absence of the severe complications seen with the natural disease in Nigeria.

4. Children who were well below the average weight for their age and sex in this community did not show more severe reactions than those above the average weight.

Measles virus for cancer therapy

Measles virus offers an ideal platform from which to build a new generation of safe, effective oncolytic viruses. Occasional so-called spontaneous tumor regressions have occurred during natural measles infections, but common tumors do not express SLAM, the wild-type MV receptor, and are therefore not susceptible to the virus. Serendipitously, attenuated vaccine strains of measles virus have adapted to use CD46, a regulator of complement activation that is expressed in higher abundance on human tumor cells than on their nontransformed counterparts. For this reason, attenuated measles viruses are potent and selective oncolytic agents showing impressive antitumor activity in mouse xenograft models. The viruses can be engineered to enhance their tumor specificity, increase their antitumor potency, and facilitate noninvasive in vivo monitoring of their spread. A major impediment to the successful deployment of oncolytic measles viruses as anticancer agents is the high prevalence of preexisting anti-measles immunity, which impedes bloodstream delivery and curtails intratumoral virus spread. It is hoped that these problems can be addressed by delivering the virus inside measles-infected cell carriers and/or by concomitant administration of immunosuppressive drugs. From a safety perspective, population immunity provides an excellent defense against measles spread from patient to carers and, in 50 years of human experience, reversion of attenuated measles to a wild-type pathogenic phenotype has not been observed. Clinical trials testing oncolytic measles viruses as an experimental cancer therapy are currently underway.

PEDIATRIC VIROLOGY

Pediatric virology is not an isolàted discipline. Rather, the syndromes associated with viral infection are modified by the unique characteristics of infancy and childhood. Fortunately for the pediatrician, and certainly for children, viral infections in childhood are rarely fatal, and are almost never serious. Future efforts of the pediatrician and virologist should be directed toward increased fetal salvage as with rubella and the prevention of severe, viral lower respiratory tract disease.

RESPONSE OF VOLTA CHILDREN TO LIVE ATTENUATED MEASLES VIRUS VACCINE

Experience so far with the Enders B-level Edmonston strain of live attenuated measles vaccine has been principally with children in the USA in whom natural measles carries a low mortality. Measles is associated with an appreciably higher mortality rate in developing countries; in Upper Volta, climate, nutritional status, degree of parasitic infestation and concurrent infections may contribute to this. The present report summarizes a pilot study in Ouagadougou, Upper Volta, designed to obtain information on the response of Volta children to Enders vaccine and to determine the feasibility of using this vaccine on a large scale.The observations indicate that Volta children, despite the hazards of natural measles, respond in essentially the same manner to live vaccine given alone or with gamma-globulin as do children in other areas. The febrile reactions which characterize infection with the attenuated measles virus were of insufficient importance to warrant the concurrent use of gamma-globulin in a forthcoming mass measles vaccination campaign in Upper Volta.