(NewsNation) — A woman from Massachusetts owes nearly $21,000 in medical bills after an unexpected bat encounter while on vacation in Arizona.

Erica Kahn was vacationing in Northern Arizona last August when a bat got trapped between her and her camera while she was photographing the night sky.

When Kahn screamed, the bat partially flew into her mouth.

Bats are one of the major rabies vectors, in part because their bite is small enough to go unnoticed. Because rabies is nearly 100% fatal once symptoms begin, anyone who interacts with a bat or finds one in their home needs to get postexposure rabies vaccines as soon as possible.

But Kahn was recently unemployed and had decided not to get COBRA coverage to extend the plan offered by her previous employer because of the cost and the fact that she was in good health.

When you leave a job, you have 60 days to sign up for COBRA, and the coverage is retroactive to the day your employer-provided coverage ended.

After her interaction with the bat, Kahn bought a private policy online and then went to get rabies vaccines. She was seen at hospitals in Arizona, Colorado and Massachusetts to get the series of shots that are given at specific intervals.

Kahn had confirmed with the insurer that emergency services were covered, but there was a 30-day waiting period on the plan. Soon, Kahn began getting bills that started adding up to more than $20,000.

Insurance companies may institute waiting periods because they don’t want people to wait to buy insurance until after something happens.

But that leaves people like Kahn powerless against bills. Waiting 30 days to get the vaccinations could have been deadly since rabies incubation periods can be as short as a week, and healthy bats don’t typically fly into people, making it more likely that the bat Kahn tangled with was infected.

Kahn has gotten a new job and negotiated one bill down by hundreds of dollars and set up a payment plan for another. She is continuing to appeal the rest of the denials.