Call it the lost summer. Call it the biggest beach scare since Jaws hit town. "Just call it over and let's get on with it," said New York's top parks official.

The fact that the summer of 1988 has ended is the only good thing many can say after Northeast beaches were sullied by medical waste and sewage."You can write off the summer of '88," said city Parks Commissioner Henry Stern. "It turned out to be the year of the plague."

With one of the hottest summers in 119 years - the temperature in Manhattan passed the 90-degree mark 32 times - it should have been a banner year.

But the tide turned in June when the first wave of medical debris, AIDS contaminated hypodermic needles, appeared in Bayonne, N.J.; and then Long Island, and Staten Island and Coney Island, and a string of beaches on the Jersey shore.

Medical waste also turned up on beaches in Connecticut, Rhode Island and Massachusetts and at Lake Erie's Cleveland Lakefront State Park in Ohio.

John J. Gaines, president of the Narragansett Chamber of Commerce in Rhode Island, believes the state benefited from the mess when tourists from New York and Connecticut headed north. He said tourism was up as much as 24 percent.

Connecticut also was plagued by hypodermic needles, syringes and high coliform counts at the beach, but the local economy did not suffer greatly; a majority of the beaches are privately owned.

In New Jersey and New York, vacationers and day visitors stayed away by the hundreds of thousands, and everyone from motel owners to local fishermen and parking lot attendants was hard hit.

"It was like a great shark scare," said Stern. "People stayed away from the beaches waiting for the all clear signal, and it never came."

More than 1,000 pieces of medical debris were scooped up at city beaches from the Bronx to Staten Island, said Stern.

An investigation failed to pinpoint the source of the problem. A state report said it was probably caused by sewer runoff, illegal dumping and a laundry list of other reasons.

"The possibility is that we will never know," said city Sanitation Department spokesman Jim Hart.

New Jersey merchants estimate it will cost the $7.7 billion-a-year shore industry more than $1 billion in lost revenue. State officials said figures aren't complete.

The Long Island tourism board estimated business was off at least 20 percent. In Brighton Beach, Brooklyn, a seashore community that depends on a hearty summer to survive, business plummeted 40 percent to 60 percent.

"We were only closed for two days in July, just two days," said Ben Lie-derman, of the Brighton Industrial Development Group. "But the scare alone . . ."

The incidents were isolated, but everyone seemed to pay the price. "They closed six beaches out of 480; four miles out of 1,600 miles of coastline," said David J. Lee, vice president of the Long Island Tourism Commission. "It was minuscule."

New Jersey officials tried to counter the bad publicity by spending an extra $575,000 in advertising to attract visitors, said Liz Thomas, deputy director of the Department of Travel and Tourism.

Some merchants plan aggressive advertising campaigns to lure beach-goers back, while others will continue pushing elected officials to make sure the issue is not dropped once the headlines - and the summer - fade.

"I didn't ever want to get involved," said Jeff Konner, owner of the Sea Spray Motel in Shipbottom, N.J. "But now I'll take a day off and go up with a group to Trenton."

"This is my life here," he said. "Everything I own is invested in this place."