Monovalent type 1 oral poliovirus vaccine among infants in India: report of two randomized double-blind controlled clinical trials.

Background: To provide the polio eradication initiative with more immunogenic oral poliovirus vaccines (OPVs), we evaluated newly developed monovalent type 1 OPV (mOPV1) among infants in India.

Methods: Two double-blind randomized controlled clinical trials compared two mOPV1s (mOPV1 A and mOPV1 B) versus trivalent OPV (tOPV X) given at birth (trial I), or assessed two products of higher-potency mOPV1 (mOPV1 C and mOPV1 D) versus regular-potency mOPV1 (mOPV1 B) or tOPV Y given at birth and at 30 days (trial II).

Results: In trial I, 597 newborns were enrolled, 66 withdrawn or excluded, leaving 531 (88.

Immunogenicity of bivalent types 1 and 3 oral poliovirus vaccine: a randomised, double-blind, controlled trial.

Background: Poliovirus types 1 and 3 co-circulate in poliomyelitis-endemic countries. We aimed to assess the immunogenicity of a novel bivalent types 1 and 3 oral poliovirus vaccine (bOPV).

Methods: We did a randomised, double-blind, controlled trial to assess the superiority of monovalent type 2 OPV (mOPV2), mOPV3, or bOPV over trivalent OPV (tOPV), and the non-inferiority of bivalent vaccine compared with mOPV1 and mOPV3.

Fractional doses of inactivated poliovirus vaccine in Oman.

Background: We conducted a clinical trial of fractional doses of inactivated poliovirus vaccine administered to infants in Oman, in order to evaluate strategies for making the vaccine affordable for use in developing countries.

Methods: We compared fractional doses of inactivated poliovirus vaccine (0.1 ml, representing one fifth of a full dose) given intradermally with the use of a needle-free jet injector device, with full doses of vaccine given intramuscularly, with respect to immunogenicity and reactogenicity.

Monovalent type 1 oral poliovirus vaccine in newborns.

Background: In 1988, the World Health Assembly resolved to eradicate poliomyelitis. Although substantial progress toward this goal has been made, eradication remains elusive. In 2004, the World Health Organization called for the development of a potentially more immunogenic monovalent type 1 oral poliovirus vaccine.

Protein-energy malnutrition among preschool children in Oman: results of a national survey.

We assessed the prevalence of underweight, wasting and stunting among preschool children in Oman from March to December 1999. Within each region, samples of males and females in the age groups 0-5, 6-11, 12-23, 24-35, 36-47 and 48-60 months were drawn from the registers of health institutions and the weight and height/length of the children were measured. The total sample comprised 19,440 children; 9911 males and 9529 females.

Immunogenicity of measles and rubella vaccines in Oman: a prospective clinical trial.

A prospective immunogenicity trial of measles and rubella vaccines was conducted in Oman. Children received measles vaccine at age 9 months and measles-rubella vaccine at age 15 months. Serum specimens were tested for measles-specific IgG and rubella-specific IgG.

Trial of a supplemental dose of four poliovirus vaccines.

Background: The immunogenicity of oral poliovirus vaccine (OPV), particularly the type 3 component, is lower in infants in most developing countries than in infants in industrialized countries. We conducted a multicenter trial in Oman to evaluate the response to a supplemental dose of four poliovirus vaccine formulations.

Methods: At nine months of age, infants were randomly assigned to receive inactivated-poliovirus vaccine (IPV), administered subcutaneously; trivalent OPV manufactured in the United States or in Europe; or monovalent type 3 OPV.

Sequential use of inactivated poliovirus vaccine followed by oral poliovirus vaccine in Oman.

Seroprevalence and geometric mean titers (GMTs) were compared at 6 and 10 months after vaccination with monovalent type 1 oral poliovirus vaccine (OPV) at 6 months and trivalent OPV at 7 and 9 months. Group 1 had received 4 doses of OPV, group 2 OPV at birth and 3 doses of OPV and inactivated poliovirus vaccine (IPV), and group 3 placebo at birth and 3 doses of IPV. A total of 547 infants completed the study.

Paralytic poliomyelitis in Oman: association between regional differences in attack rate and variations in antibody responses to oral poliovirus vaccine.

Variation in attack rates of paralytic disease by region during the 1988-1989 epidemic of type 1 poliomyelitis in Oman provided the stimulus to test the hypothesis that these observations were due to regional differences in the response of infants to trivalent oral poliovirus vaccine (OPV). Seroprevalence studies of 394 children born during the outbreak were conducted in six different regions of Oman and in two socioeconomic status (SES) groups in the capital city of Muscat; a seroconversion study was also carried out in 105 infants born after the outbreak. Seroprevalence rates by region after receipt of at least three doses of OPV ranged from 90% to 100% (median 94%) to poliovirus type 1, and from 86% to 100% (median 97%) to type 2, and from 47% to 79% (median 72%) to type 3, with the lowest rates observed in regions with the highest incidence of type 1 paralytic disease.

Attributable risk of DTP (diphtheria and tetanus toxoids and pertussis vaccine) injection in provoking paralytic poliomyelitis during a large outbreak in Oman.

Although injections administered during the incubation period of wild poliovirus infection have been associated with an increased risk of paralytic poliomyelitis, quantitative estimates of the risk have not been established. During a poliomyelitis outbreak investigation in Oman, vaccination records were reviewed for 70 children aged 5-24 months with poliomyelitis and from 692 matched control children. A significantly higher proportion of cases received a DTP (diphtheria and tetanus toxoids and pertussis vaccine) injection within 30 days before paralysis onset than did controls (42.

Outbreak of paralytic poliomyelitis in Oman: evidence for widespread transmission among fully vaccinated children.

From January, 1988, to March, 1989, a widespread outbreak (118 cases) of poliomyelitis type 1 occurred in Oman. Incidence of paralytic disease was highest in children younger than 2 years (87/100,000) despite an immunisation programme that recently had raised coverage with 3 doses of oral poliovirus vaccine (OPV) among 12-month-old children from 67% to 87%. We did a case-control study (70 case-patients, 692 age-matched controls) to estimate the clinical efficacy of OPV, assessed the immunogenicity of OPV and extent of poliovirus spread by serology, retrospectively evaluated the cold chain and vaccine potency, and sought the origin of the outbreak strain by genomic sequencing.