Adverse event reports following vaccination for Lyme disease: December 1998-July 2000

The vaccine adverse event reporting system (VAERS) monitors vaccine safety post-licensure. Although events reported to VAERS are not necessarily causally associated with vaccination, VAERS reports can be used to identify possible safety concerns that occur at too low a rate to have been identified prior to licensure.

To evaluate adverse events following Lyme disease vaccination reported to VAERS during the first 19 months of the vaccine's licensure.

Analysis of all VAERS reports of adverse events following vaccination for Lyme disease in the US from 28 December 1998 to 31 July 2000.

We evaluated reported adverse events for unexpected patterns in age, gender, time to onset, dose number, and clinical characteristics and compared them to adverse events observed in clinical trials of this vaccine.

Over 1,400,000 doses were distributed and 905 adverse events were reported to VAERS, 440 in men and 404 in women, with ages ranging from 10 to 82 years. The majority (56%) of adverse events occurred after administration of the first dose. The most frequently reported adverse events were arthralgia (250), myalgia (195), and pain (157). There were 59 reports coded as arthritis, 34 as arthrosis, 9 as rheumatoid arthritis, and 12 as facial paralysis. Sixty-six (7.4%) events were classified as serious, involving life-threatening illness, hospitalization, prolongation of hospitalization, persistent or significant disability/incapacity, or death. Twenty-two hypersensitivity reactions were reported.

Based on reporting to VAERS, we did not detect unexpected or unusual patterns of reported adverse events following Lyme disease vaccine administration, other than hypersensitivity reactions, compared with adverse events observed in clinical trials.