Atlanta ? About one in 10 doctors who vaccinate privately insured children are considering dropping that service largely because they are losing money when they do it, according to a new survey.

A second survey revealed startling differences between what doctors pay for vaccines and what private health insurers reimburse: For example, one in 10 doctors lost money on one recommended infant vaccine, but others made almost $40 per dose on the same shot.

The survey was revealing even to some doctors. “Many physicians really weren’t aware and that they were getting reimbursed so little,” said Dr. Gary Freed of the University of Michigan, a co-author of both articles published in the December issue of the journal Pediatrics.

The studies are the first to attach numbers to doctors’ long-simmering complaints that they are only breaking even — or even losing money — when they give shots.

Experts say there’s no evidence that significant numbers of doctors are quitting the vaccination business yet because of financial concerns.

But health officials are worried. Reimbursement concerns were behind an exodus of doctors from vaccine programs in the 1980s, which contributed to a terrible resurgence of measles in 1989-91 that caused 11,000 hospitalizations and 123 deaths.