Washington ? A bill compensating people injured or killed by the smallpox vaccine was defeated Monday in the House amid debate over the size of the payments.

Despite widespread agreement that compensation is needed for people injured or killed by the vaccine, which carries rare but serious risks, the House has been unable to agree on a package of benefits.

On Monday, the House defeated, 206-184, a GOP-backed bill establishing a set of payments. Republicans were invoking rules needing a two-thirds majority, but they failed to get even a simple majority.

Democrats said the bill was not generous enough to persuade health care workers and others to sign up for the vaccine.

All involved with the government’s smallpox program believe it’s imperative that Congress establish payments for those injured or killed by the vaccine. Congress has already barred most lawsuits that might stem from the vaccine, and state workers’ compensation programs offer only spotty coverage.

The number of people volunteering for the shot is well below what was expected, partly because of concerns that injured people won’t be compensated for medical expenses, lost work time and other expenses.

The national vaccination program also has suffered from questions about the relationship between the vaccine and heart problems after three people died of heart attacks after being inoculated.

While experts suspect the vaccine is probably not to blame, nine states — Arizona, California, Illinois, Maine, Michigan, Nevada, New York, Vermont and Washington state — have suspended their programs during an investigation.