A prospective evaluation of posterior capsule opacification in eyes with diabetes mellitus: a case-control study.

AIM: To compare the development of posterior capsule opacification (PCO) between eyes with and without diabetes mellitus after single-piece hydrophobic acrylic intraocular lens implantation 4 years postoperatively. METHODS: In this prospective, observational case-control study carried out at Iladevi Cataract and IOL Research Centre, Ahmedabad, India, 75 consecutive eyes with diabetes mellitus (cases) were compared with 75 age-matched eyes with age-related cataract (controls). A detailed, preoperative and posterior segment evaluation was carried out in eyes with diabetes mellitus to detect the presence or absence of diabetic retinopathy (DR). The Mann-Whitney U-test was applied to compare the differences in the development of PCO between the two groups. RESULTS: There was no difference in median PCO between cases and controls at 1 month (2.0 vs 1.50, P<0.068), but cases had a higher median PCO at 12 months (2.95 vs 1.30, P<0.001). At 4 years, there was no significant difference in median PCO between cases and controls (3.75 vs 2.25, P=0.273). The duration of diabetes increased the incidence of PCO at 4 years (P=0.02). Severity of DR had no influence on the progress of PCO at 4 years (P=0.69). CONCLUSION: Diabetes mellitus did not increase the incidence of PCO at 4 years. The duration of diabetes increased the risk of PCO. The severity of retinopathy did not influence the development of PCO.

Antibody response of children immunized with poliovaccines: an evaluation using two strains of poliovirus type 1.

Neutralizing antibody response of children immunized with either OPV (3 doses), or IPV (2 doses) was evaluated against poliovirus type 1 Sabin vaccine strain and a local neurovirulent isolate. Both vaccines elicited significantly better antibody response against the vaccine strain than against the neurovirulent isolate. Moreover, approximately 35 per cent of sera contained very low levels of antibody against the virulent virus in spite of good antibody titre against the vaccine strain. The observed difference in antibody response to the wild and the vaccine strains was significant. The differential immune response could be one of the reasons of paralytic disease observed even after administration of OPV (3), in some children if infecting virus dose is high, as in case of urban slums in endemic areas.

Intratypic characterization of poliovirus type 1 isolates.

Intratypic serodifferentiation of 607 strains of poliovirus type 1 isolated from diverse epidemiological groups, was carried out using strain-specific antisera and monoclonal antibodies. The isolates were from patients of paralytic poliomyelitis from Marathwada (an epidemic area) and Bombay (endemic area) and from healthy children from Emmaneshwaram (vaccinated area). From Marathwada where mass scale vaccination with oral poliovirus vaccine (OPV) was performed to contain the spread of the epidemic, non-vaccine-like and vaccine-like virus strains were isolated. Only non-vaccine-like virus strains were detected among the Bombay isolates. In Emmaneshwaram mass-scale vaccination performed in 1986 had earlier led to the replacement of the wild poliovirus with the vaccine strains. However, even though systematic OPV immunization reached 93 per cent coverage in 1987 and 1988, majority of isolates from Emmaneshwaram were found to be non-vaccine-like. Results showed that routine immunization of children with OPV was not sufficient to displace the wild virus. A small number of antigenic variants were detected. The frequency of such variants was more when mass-scale vaccinations were performed after paralytic poliomyelitis outbreaks. Using a panel of monoclonal antibodies epitope mapping of these variants was performed.

Efficacy of three doses of oral polio immunization beginning within the first four days of life.

A study was carried out to test the efficacy of oral polio immunization commencing in the newborn period. In Group A, 47 term newborn infants were given trivalent oral polio vaccine (TOPV) within the first four days, at one month and at two months. In Group B, 21 infants were given TOPV at 3, 4 and 5 months. The seroconversion rates for types 1, 2 and 3 were 87.2, 95.7 and 72.3%, respectively in Group A and 85.7, 95.2 and 66.7%, respectively in Group B after 3 doses of TOPV, the differences being insignificant. Oral polio immunization beginning in the newborn period was as effective as when commenced at 3 months of age. Before immunization, the number of babies with protective titers against polioviruses were significantly more in Group A as compared to Group B. Thus, the later onset of immunization schedule leaves more children susceptible to poliomyelitis during the first 3 months of life.

Poliomyelitis surveillance and vaccine efficacy in Bombay, 1982-87.

Reported are updated data on poliomyelitis surveillance in Bombay for the period 1982-87 and estimates of the efficacy of oral poliovaccine (OPV) calculated by the case exposure method, using two approaches. The first, a screening technique that used only data on the reported number of doses of vaccine administered and the immunization status of all poliomyelitis cases, appeared to underestimate the true vaccine efficacy. In the more rigorous second technique, which used data for children of the same age group, geographical areas, and study year, obtained from immunization coverage surveys, and information on the immunization status of poliomyelitis cases, the results indicate that the OPV vaccine efficacy for fully immunized children aged 12-23 months exceeded 90%. These findings show that the estimated efficacy of OPV is high in Bombay and that, in general, vaccine efficacy should be re-estimated using more rigorous techniques if preliminary screening estimates indicate a lower than expected efficacy. In Bombay, poliomyelitis therefore results primarily from a failure to fully vaccinate all eligible children rather than as a result of vaccine failure. Furthermore, the age distribution of cases suggests that the strategy of focusing immunization activities on children aged under 1 year is epidemiologically correct.

Poliomyelitis surveillance and vaccine efficacy in Bombay, 1982-87

Reported are updated data on poliomyelitis surveillance in Bombay for the period 1982-87 and estimates of the efficacy of oral poliovaccine (OPV) calculated by the case exposure method, using two approaches. The first, a screening technique that used only data on the reported number of doses of vaccine administered and the immunization status of all poliomyelitis cases, appeared to underestimate the true vaccine efficacy. In the more rigorous second technique, which used data for children of the same age group, geographical areas, and study year, obtained from immunization coverage surveys, and information on the immunization status of poliomyelitis cases, the results indicate that the OPV vaccine efficacy for fully immunized children aged 12-23 months exceeded 90 percent

These findings show that the estimated efficacy of OPV is high in Bombay and that, in general, vaccine efficacy should be re-estimated using more rigorous techniques if preliminary secreening estimates indicate a lower than expected efficacy. In Bombay, poliomyelitis therefore results primarily from a failure to fully vaccinate all eligible children rather than as a result of vaccine failure. Furthermore, the age distribution of cases suggests that the strategy of focusing immunization activities on children aged under 1 year is epidemiologically correct(AU)

Measles in India.

Measles is an important cause of morbidity and mortality among the children of India. In spite of this it is not considered a serious problem by the health authorities. Practically no cases are reported, and only those children with significant complications are hospitalized. Thus hospital records do not reflect the magnitude of the problem. In recent years attention has been focused on the evaluation of the morbidity and mortality due to measles in India. In the absence of reliable estimates, it is presumed that almost everyone in India suffers from measles before the age of 10 years. Hospital-based studies have found that 20%-70% of children with measles develop minor and major complications. On the basis of the few hospital-based studies and community surveys, it appears that the mortality rate due to measles is 3%-15%, depending on the health-care system in the community. All available data point to the necessity of immunization programs against measles, but logistical and economic constraints have prevented introduction of measles immunization in the Expanded Programme on Immunization. A limited experience with measles vaccine in India has shown that practically no cases occur among immunized children and that seroconversion rates are excellent. It is urgent to create awareness among health authorities, physicians, and health workers of the problem of measles.