WARWICK — With drug companies scrambling to develop a swine flu vaccine in case the illness stages a resurgence this fall, the drug-testing company Omega Medical Research said Tuesday it has been hired to test three of the vaccines in a variety of age groups.

The tests, in which volunteers will receive two treatments beginning in August, are designed to assess the safety of the three vaccines, each made by different unnamed firms, for as long as 180 days.

The vaccines will also be given in varying doses to see which one produces the strongest immune reaction.

Omega co-owner Lynne Haughey, a nurse practitioner, said one study will enroll up to 300 adults. Participation will require seven clinic visits and volunteers will be paid up to $540.

A smaller study of a different vaccine will involve injecting 60 children, ages 2 to 17, and require five visits. The payment will be up to $350.

The third vaccine, to be sprayed in the nose, will be tested in infants and toddlers, ages 6 months to 35 months. Omega is looking for 40 children to participate in that study. The payment will be as much as $520.

The vaccines are being tested at other sites as well, said Haughey.

She said she doesn’t expect to see serious problems with the vaccine because the technique for developing them “is a lot like developing them for season flu.

“I think they can predict somewhat what the side effects will be in people,” she said. “Typically, what you see in every vaccine is that [people] may develop fever, some malaise, some fatigue and muscle aches that may last up to 72 hours.”

The vaccines that are approved by the Food and Drug Administration are not expected to be on the market until November or early December.

People who wish to volunteer can call (401) 739-3573.

gemery@projo.com