A randomized placebo-controlled trial of acetaminophen for prevention of post-vaccination fever in infants.

BACKGROUND: Fever is common following infant vaccinations. Two randomized controlled trials demonstrated the efficacy of acetaminophen prophylaxis in preventing fever after whole cell pertussis vaccination, but acetaminophen prophylaxis has not been evaluated for prevention of fever following contemporary vaccines recommended for infants in the United States. METHODS: Children six weeks through nine months of age were randomized 1:1 to receive up to five doses of acetaminophen (10-15 mg per kg) or placebo following routine vaccinations. The primary outcome was a rectal temperature ≥38°C within 32 hours following the vaccinations. Secondary outcomes included medical utilization, infant fussiness, and parents' time lost from work. Parents could request unblinding of the treatment assignment if the child developed fever or symptoms that would warrant supplementary acetaminophen treatment for children who had been receiving placebo. RESULTS: A temperature ≥38°C was recorded for 14% (25/176) of children randomized to acetaminophen compared with 22% (37/176) of those randomized to placebo but that difference was not statistically significant (relative risk [RR], 0.63; 95% CI, 0.40-1.01). Children randomized to acetaminophen were less likely to be reported as being much more fussy than usual (10% vs 24%) (RR, 0.42; 95% CI, 0.25-0.70) or to have the treatment assignment unblinded (3% vs 9%) (RR, 0.31; 95% CI, 0.11-0.83) than those randomized to placebo. In age-stratified analyses, among children ≥24 weeks of age, there was a significantly lower risk of temperature ≥38°C in the acetaminophen group (13% vs. 25%; p = 0.03). CONCLUSION: The results of this relatively small trial suggest that acetaminophen may reduce the risk of post-vaccination fever and fussiness. TRIAL REGISTRATION: Clinicaltrials.gov NCT00325819.

Immunogenicity of varying dosages of 7-valent pneumococcal polysaccharide-protein conjugate vaccine in seniors previously vaccinated with 23-valent pneumococcal polysaccharide vaccine.

In this dose-ranging study 220 seniors who had received the 23-valent pneumococcal polysaccharide (PnPS) vaccine at least 5 years prior to enrollment were assigned to receive one of four volumes (0.1, 0.5, 1 or 2 ml) of 7-valent pneumococcal conjugate (PnC) vaccine or a 0.5 ml dose of 23-valent PnPS vaccine. All participants received a reduced challenge dose of 0.1 ml of PnPS vaccine 1 year after enrollment. There was evidence of a dose response to PnC vaccine and antibody levels in the 1 ml PnC group tended to be significantly higher than in the PnPS group. A booster response to the challenge vaccination was not observed. Administration of a 1 ml dose of PnC vaccine is more immunogenic than 0.5 ml of PnPS vaccine in elderly adults previously vaccinated with PnPS vaccine.

Retrospective population-based assessment of medically attended injection site reactions, seizures, allergic responses and febrile episodes after acellular pertussis vaccine combined with diphtheria and tetanus toxoids.

BACKGROUND: Since 1997 diphtheria-tetanus toxoids-acellular pertussis (DTaP) vaccines have been recommended for the five dose pertussis vaccination series. To assess rates of medically attended injection site reactions (ISRs), seizures, allergic responses and febrile episodes after Tripedia DTaP vaccine administered in the context of routine care, we conducted a retrospective assessment among the population of Group Health Cooperative from 1997 through 2000. METHODS: Administrative databases were used to identify medical visits linked with diagnostic codes potentially indicative of ISRs, seizures, allergic responses and febrile episodes after DTaP vaccine. Outcomes were confirmed by medical record review. RESULTS: During the study period 76 133 doses of DTaP were administered. Of the 26 ISRs identified, 6 followed DTaP given as the fourth dose and 18 followed DTaP given as the fifth dose, for rates of 1 per 2779 and 1 per 900 vaccinations, respectively. During the study period nearly all children receiving DTaP as the fifth dose had received whole cell pertussis vaccine for their primary series, and all of the fifth dose ISRs were among that group. Four of those reactions involved the entire upper arm. The rate of febrile seizures within 2 days of DTaP among children <2 years of age was 1 per 19 496 vaccinations. CONCLUSIONS: The low rate of febrile seizures and other serious events confirms the safety of DTaP vaccine. The risk of medically attended ISRs was highest with DTaP given as the fifth dose, and whole arm reactions were reported, but medically attended ISRs were relatively uncommon and were self-limited.