A placebo-controlled trial of a pertussis-toxoid vaccine.

BACKGROUND: Although many whole-cell vaccines have been effective in preventing pertussis, these vaccines are difficult to standardize and can produce side effects. In Sweden, pertussis became endemic during the 1970s despite vaccination. Because of its limited efficacy, the Swedish-made whole-cell vaccine was withdrawn in 1979. METHODS: To evaluate the efficacy of an acellular vaccine consisting of pertussis toxin inactivated by hydrogen peroxide (pertussis toxoid), we conducted a randomized, double-blind, placebo-controlled trial in Sweden. Infants were vaccinated with either diphtheria and tetanus toxoids alone (DT toxoids, 1726 infants) or diphtheria, tetanus, and pertussis toxoids (DTP toxoids, 1724 infants) at 3, 5, and 12 months of age. RESULTS: There were no serious reactions. With the pertussis vaccine there were slightly more local reactions than with the DT toxoids alone, but the rates of postvaccination fever were the same. The main period of surveillance, which began 30 days after the third vaccination, continued for a median of 17.5 months. There were 312 cases of pertussis (72 in the DTP-toxoids group and 240 in the DT-toxoids group) that met the clinical criterion (paroxysmal cough lasting > or = 21 days) and laboratory criteria for pertussis as defined by the World Health Organization. The efficacy of this acellular vaccine was 71 percent (95 percent confidence interval, 63 to 78 percent). The recipients of DTP toxoids who had pertussis had cough of shorter duration than the recipients of DT toxoids, and fewer had whooping and vomiting. The vaccine efficacy after two doses was 55 percent (95 percent confidence interval, 12 to 78 percent), on the basis of 14 cases in the DTP-toxoids group and 31 in the DT-toxoids group that met the definition of the World Health Organization. CONCLUSIONS: A pharmacologically inert, acellular pertussis-toxoid vaccine that is easily standardized is safe and confers substantial protection against pertussis.

Safety and immunogenicity of hydrogen peroxide-inactivated pertussis toxoid in 18-month-old children.

The immunogenicity and adverse effects of an acellular pertussis vaccine consisting of a purified pertussis toxin inactivated with hydrogen peroxide (PTxd) was evaluated. Children aged 15 to 30 months were injected with 10 (n = 33) or 50 micrograms (n = 34) of PTxd or with diphtheria and tetanus toxoids and whole cell pertussis vaccine (DTP) (n = 34). All children had previously received three doses of DTP during infancy. Both dosages of PTxd induced higher IgG antibody (p less than 0.05 for 10 micrograms dose and p less than 0.01 for 50 micrograms dose) and pertussis antitoxin responses (p less than 0.01 for 50 micrograms dose) than DTP. The 50 micrograms dose gave slightly higher (though not significantly) antibody responses than the 10 micrograms dose of PTxd. None of the vaccines induced detectable IgM or IgA antibody responses to pertussis toxin. At 24 h, local reactions occurred in none of the children injected with 10 micrograms PTxd, 12% with 50 micrograms PTxd and 78% with DTP. Fever at 24 h occurred in 13% after 10 micrograms PTxd, in none after 50 micrograms PTxd and in 53% after DTP. Recipients of DTP, but not of PTxd, had significant increases in neutrophils and decreases in lymphocytes and haematocrit at 24 h (all p less than 0.05). None of the groups showed changes in blood glucose at 24 h. PTxd induced pertussis toxin antibody levels similar to those observed in patients convalescing from natural pertussis. This acellular pertussis vaccine deserves further evaluation for safety and immunogenicity in infants and for efficacy in preventing pertussis.

O-specific side-chain toxin-protein conjugates as parenteral vaccines for the prevention of shigellosis and related diseases.

Only indirect evidence has been cited to document that lipopolysaccharide-mediated virulence at the bacterial level and serum antibodies to the O-specific side chain of the lipopolysaccharide molecule may prevent shigellosis. Our proposed use of the B subunit of Shiga toxin as a carrier protein is based upon evidence (even more indirect) that serum antitoxin may reduce the severity of dysentery and diarrhea. Because animal models of disease may provide information inapplicable to the prediction of vaccine-induced protective immunity, we suggest that clinical trials in the population at risk should be started after successful completion of the safety and immunogenicity phases of vaccine development in laboratory animals and in the target population. Clinical studies of shigella vaccines are difficult because of the many causes of dysentery in a population with a high rate of intestinal disease.

Prevention of typhoid fever in Nepal with the Vi capsular polysaccharide of Salmonella typhi. A preliminary report.

We conducted a pilot study followed by a large clinical trial in Nepal of the use of the capsular polysaccharide of Salmonella typhi (Vi) as a vaccine to prevent typhoid fever. In the pilot study, involving 274 Nepalese, there were no significant side effects of the Vi vaccine; about 75 percent responded with a rise in serum antibodies of fourfold or more. In the clinical trial, residents of five villages were given intramuscular injections of either Vi or, as a control, pneumococcus vaccine dispensed in coded, randomly arranged, single-dose syringes. There were 6907 participants, of whom 6438 were members of the target population (5 to 44 years of age); each was visited every two days. Those with temperatures of 37.8 degrees C or higher for three consecutive days were examined and asked to give blood for culture. Typhoid was diagnosed as either blood culture-positive or clinically suspected on the basis of bradycardia, splenomegaly, and fever, with a negative blood culture. Seventeen months after vaccination, the codes were broken for the 71 patients meeting the criteria for either culture-positive or clinically suspected typhoid. The attack rate of typhoid was 16.2 per 1000 among the controls and 4.1 per 1000 among those immunized with Vi (P less than 0.00001). The efficacy of Vi was 72 percent in the culture-positive cases, 80 percent in the clinically suspected cases, and 75 percent in the two groups combined. These data provide evidence that Vi antibodies confer protection against typhoid. Surveillance continues to determine the duration of Vi-induced immunity.

The triple helix--NIH, industry, and the academic world.

Spectacular accomplishments in biomedical research have given birth to what is now perceived as a biological revolution, an epoch in which man has acquired the skill to manipulate the fundamental unit of heredity, the gene. This revolution carries with it the prospect of remarkable opportunities to improve the quality of life and to probe with increasing precision the mysteries of cellular organization and function. It comes, however, at a time when the opportunity to exploit this new knowledge may be limited by a significant reduction in federal support of basic research, and a situation which prompts universities and other centers of scientific activity to seek funding from industrial patrons. This trend has generated a new constellation of institutional challenges, for one apparent result of industrial sponsorship of university-based biomedical research is a threat to university governance as altered allegiances emerge and as the potential for financial gain appears almost limitless. This essay explores background issues leading to these new alliances, seeks to identify some of the central problems emerging for university administrators, faculty, and students, and then poses a key question: Can industrial support for university-based biomedical research fill the apparent short-fall in federal dollars in the foreseeable future? An analysis of available data indicates that this outcome is unlikely either now or in the years ahead.