Low risk of recurrence of oculorespiratory syndrome following influenza revaccination

Abstract

Background: During the 2000-2001 influenza vaccination season, a new adverse event associated with the influenza vaccine, called oculorespiratory syndrome (ORS), was identified in Canada. We examined the risk of recurrence of ORS for individuals affected in 2000-2001 who were revaccinated in the community setting in 2001-2002.

Methods: We conducted a telephone survey in May 2002 in which participants were asked whether they had been revaccinated in the 2001-2002 immunization season and whether they had experienced any recurrence of ORS or any other adverse event. Eligible individuals (n = 609) included residents of British Columbia aged 18 years or more who had reported any type of adverse event associated with the influenza vaccine in 2000 and who had participated in a survey in September 2001 that characterized their adverse event experience.

Results: The response rate to this survey was 92% (561 of 609 people approached). Of the 561 participants, 202 were revaccinated in 2001. Among the 202 revaccinated, 122 individuals had previously reported ORS in 2000: 40 had described their ORS experience in 2000 as mild (present but not bothersome), 44 as moderate (interrupting daily activities), 35 as severe (preventing daily activities) and 3 did not provide specific details. Six of the 122 individuals experienced a recurrence of ORS following revaccination. The estimated risk of recurrence for ORS following revaccination in the community setting was 5% (95% confidence interval 2.2%-10.5%). Four of the 6 individuals described their ORS recurrence in 2001 as milder than the ORS they had experienced in 2000.

Interpretation: We found a low risk of recurrence of ORS for individuals previously affected in 2000 when they were revaccinated in 2001, including those whose ORS in 2000 had prevented daily activities but was not clinically severe. Health care providers should be confident in the safety of recommending revaccination of these individuals. As with all vaccines, however, a detailed risk-benefit assessment should be undertaken before revaccination of people whose previous adverse event experience may have included collapse, respiratory difficulty (including throat tightness) and/or chest discomfort requiring emergency intervention.

Fig. 1: Percentage of study participants revaccinated in 2001 by objective indicators of ORS severity in 2000. ORS = onset of bilateral red eyes or respiratory symptoms (cough, wheeze, chest tightness, difficulty breathing or sore throat) or facial edema within 24 hours following influenza vaccination.