Revaccination with the pneumococcal vaccine is recommended after five years for patients older than 65 who were initially vaccinated before age 65 and for patients age 64 or younger who are immunocompromised. To study the safety of revaccination, Jackson and colleagues compared reactions after first vaccination with those experienced after revaccination among 1,400 patients.

The reactions in 901 patients who received their first vaccination were compared with those in 513 patients who received a second vaccination at least five years after the first one. Patients ranged from 50 to 74 years of age and were excluded if they had reported any significant adverse events following their first pneumococcal vaccination. Each patient kept a diary to record temperature twice daily for the week following the injection. Adverse reactions, including erythema and induration, were recorded for 13 days after the vaccination.

No serious adverse events occurred in any of the patients. Patients who received a second pneumococcal vaccination experienced significantly more injection site reactions than did those who were vaccinated for the first time. Soreness of the arm was reported by 74 percent of the revaccinated group and by 57 percent of the group receiving a first vaccination (relative risk: 1.3).

A sizable local reaction, defined as 10.2 cm of redness, developed in 11 percent of the revaccinated group, compared with 3 percent of the group receiving the vaccine for the first time.

The authors conclude that local reaction is significantly more likely in patients who are revaccinated at least five years after the initial pneumococcal vaccination. However, the redness, swelling and pain are self-limited and do not constitute a reason to not recommend revaccination at the appropriate interval.