It has been difficult over the years to get a good statistical handle on the size of the AIDS problem in this country. But by the latest and most sophisticated measurements, the disease continues to frustrate federal and local efforts to rein it in.

A recent report from the federal Centers for Disease Control and Prevention showed that the number of people newly infected each year with H.I.V., the virus that causes AIDS, is 40 percent higher than previously estimated. The report, based on new technology that allows more precise estimates, found that 56,300 people around the country became newly infected in 2006, well above the 40,000 cited in recent years.

Using the new formula, the New York City health department estimated that the virus was spreading here at three times the national rate and had infected nearly 4,800 people in 2006.

Greater efforts to control the virus by all levels of government are obviously required. There is an urgent need to focus even more on black and Hispanic communities, which are disproportionately infected, and on gay and bisexual men, who are increasingly becoming less cautious.

While the Bush administration has shown leadership in the fight against global AIDS, committing billions of dollars, domestic spending has been essentially flat. The C.D.C. spends some $750 million a year to prevent new infections. That effort has helped hold the number of new H.I.V. infections stable since 2000 even as the number of people living with the AIDS virus has risen, providing more opportunities for transmission. Federal officials need to redouble their efforts to lower the rate of new infections.

The city’s department of health distributes tens of millions of condoms annually, provides a needle-exchange program for intravenous drug users, tries hard to identify new cases and urges the sex partners of infected patients to get tested. But more is clearly needed.

The remedies should include a stronger education campaign in high-risk populations and free and easily accessible testing to find infected people. Roughly one-quarter of all infected people are unaware of their status.

It has been three decades since AIDS made its appearance. There was hope not long ago that the nation was bringing infections under control. The recent bad news means that the crisis is still with us.