Four doses of an experimental vaccine to protect against Lyme disease reduced the number of tick-borne infections by more than 70 percent, according to Pfizer and Valneva, the pharmaceutical companies developing the shot.

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Pfizer said in a statement the companies are “confident in the vaccine’s potential” and plan to submit the data to regulatory authorities seeking approval. If successful, it could become the only Lyme disease vaccine available for people — although it would not be the first.

A previous Lyme disease vaccine, called LYMErix, was approved in 1998. But it became controversial because of reports of adverse events following vaccination, and it was pulled from the market four years later due to poor sales.

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The results of the trial, which tested the vaccine against a placebo in 9,400 people ages 5 and up, have not yet been published or peer reviewed. Pfizer said in its statement that its late-stage clinical trial just missed a statistical cutoff for success, because there were fewer than expected cases of Lyme disease in the trial.