John D. Farquhar

Clinical and serological evaluation of a meningococcal polysaccharide vaccine groups A, C, Y, and W135.

Abstract The clinical evaluation of a meningococcal polysaccharide vaccine containing groups A, C, Y, and W135 antigens was described. The vaccine was found to be clinically acceptable and a significant antibody response was detected by both a bactericidal assay and a solid-phase radioimmune assay.

Intranasally administered rubella vaccine.

Abstract The RA27/3 strain of rubella virus, which is an effective attenuated strain when given subcutaneously, is also immunogenic when given intranasally. Given in a dose of 1000 plaque-forming units (P.F.U.) in the form of nose drops, the virus produced antibodies in 93% of subjects (mainly children); a dose of 100 P.F.U. immunised 50% of subjects. Clinical reaction was absent except for occasional lymphadenopathy. Nasopharyngeal virus excretion was sporadic, and there was no spread to contacts. Antibody responses to intranasal vaccination were equivalent to those obtained after subcutaneous inoculation.

Follow-up on reubella vaccinations and experience with subclinical reinfection

Rubella antibody titers for a group to women vaccinated soon after delivery have decreased slightly after two years. None of their unvaccinated infants—even those who were breast-fed—had any serologic evidence of exposure to rubella virus. Antibody levels have been determined at annual intervals for three years on a group of institutionalized children. The geometric mean titer fell during the second year, then unexpectedly rose during the third year suggesting subclinical reinfections. The incidence of subclinical reinfection was very low among RA 27/3 vaccinees and naturally immune children, but it was 26 per cent among recipients of the Cendehill vaccine. Results suggest that with presently licensed rubella vaccines it is not possible to produce a “herd immunity,” at least, not in an institutional population.

Experience with rubella and rubella immunization in institutionalized children

Serial monitoring of rubella hemagglutination-inhibiting antibodies in institutionalized children revealed that 4 of 16 nonvaccinated rubella-susceptible children had developed antibodies and 4 of 29 children immunized with Cendehill rubella vaccine had a fourfold or greater rise in antibody titer during the same 4 year interval. This apparent spread of wild virus occurred within three building with a population estimated to be 91 per cent “immune.” The vaccinees have shown a slight fall in hemagglutination-inhibiting antibody titers over the four years, and both the vaccines and naturally immune children who experienced the “booster” response had titers lower than the others. These observations cast doubt on the ability of “herd immunity” to prevent the spread of wild rubella virus.

Clinical and Serological Evaluation of Purified Polysaccharide Vaccines Prepared from Neisseria meningitidis Group Y

Summary The clinical and serological testing of a group Y meningococcal polysac-charide vaccine is described. Only minor local reactions at the injection site were observed. High levels of bactericidal antibody were observed in 93% of the individuals 3 weeks after receiving the vaccine.

Evaluation of sulfaethylthiadiazole (SETD) in common infectious states in children

Summary 1. Sulfaethylthiadiazole (SETD), a newly available sulfonamide, was used to treat 512 pediatric patients who had bacterial infections (chiefly of the respiratory and urinary tracts) commonly seen in everyday practice. SETD in tablet or liquid form was administered to 298 patients; 146 were given the drug as a sustained-release suspension. An additional sixty-eight patients (with advanced infections) received an initial injection of procaine penicillin followed by SETD therapy. 2. Results of therapy indicate that SETD is a highly effective antibacterial agent. SETD shortened the course of infection and prevented any extension or complication of the original infection in about 97 per cent of the patients. A combination of SETD therapy and an initial injection of penicillin proved effective in advanced and severe infections. 3. Of the 298 patients treated with SETD in tablet or liquid form, fifteen developed mild diarrhea, one a mild rash, and one vomited. Mild diarrhea was observed in only one of the 146 patients who received the sustained-release suspension. None of the patients developed gross hematuria or other renal complications. Except for one skin rash, there was no other evidence of sensitization or toxicity related to the administration of SETD. 4. Therapeutic blood concentrations (8 to 15 mg. per cent) of SETD were obtained with the plain drug, provided the drug was given every six hours. A single dose of the sustained-release suspension produced therapeutic blood concentrations for twelve hours. 5. An average of only 2.2 per cent of SETD undergoes acetylation in the blood, indicating that more than 95 per cent of the total dose is available for antibacterial activity.

Cendehill strain of rubella vaccine: Clinical evaluation

Rubella vaccine, the Cendehill strain, was evaluated clinically and by measuring the hemagglutination-inhibition antibody response in the sera of both children and young women. In both groups of susceptible individuals, an antibody response occurred in over 99 per cent. The titer in children has remained fairly constant for at least 9 months. The Cendehill vaccine produces virtually no side effects in children and a low incidence in young women. Rubella virus was isolated from the nasopharynx of one half of the vaccinees, but there was no evidence of communicability. Eighteen months after vaccination, 4 children were challenged by inoculation with unattenuated rubella virus; none had any clinical manifestations of rubella.