September 25, 1981

Thousands of youngsters were turned away from New York City's public schools yesterday because they lacked either proof of immunization against childhood diseases or permission from their parents for the schools to give them the legally required inoculations. The teachers of a school system struggling to reduce its dropout rate found themselves in the awkward position of directing students to leave classes and not to return until they had complied with the law. School officials are hoping that most students barred yesterday will provide the required documents today so that they can be readmitted. They say that the attendance bureau will look into the cases of those who are absent for more than a few days.

The Consumer Price Index, the nation's most widely followed measure of inflation, climbed eight-tenths of 1 percent in August, helped by a moderation in the increase of housing costs, the Labor Department reported today. The results, while containing some mildly unsettling data on food and clothing, were nevertheless broadly in line with the expectations of economists and were regarded as confirmation that the big 1.2 percent jump in July was largely a fluke related to the cost of housing. Consumer prices rose a fu ll 1 percent in the New York-No rtheastern New Jersey area. (Page D6.) ''I think it is a pretty good report,'' Lacy H. Hunt, ch ief economist for the Fidelity Bank of Philadelphia, said of t he national figures. ''Most importantly,'' he added, ''the in flation performance in August is really considerably better than t he eighttenths of 1 percent reported would indicate.'' Despit e the exceptionally high mortgage rates that helped push the mon thly inflation level back to double-digit annual rates during t he latest two months - 15.2 percent in July and 10.6 percent in Augu st - the longer-term downward trend appeared to remain intact.

For the better part of a month, Jack Henry Abbott stayed a step ahead of Federal authorities, who were armed with information from the New York City police as they traced his path. They tracked him from flophouses in the French quarter of New Orleans to bunkhouses in the South Louisiana oilfields before apprehending him yesterday afternoon in a pipeline inspection yard a mile east of here. Mr. Abbott, a convict and author who had been befriended and employed by Norman Mailer, had been on the run since shortly after dawn on July 18, when Richard Adan, a 22-year-old aspiring actor and playwright, was stabbed to death outside the Bini-Bon restaurant at Second Avenue and East Fifth Street in Manhattan, where he worked as a waiter. Late this afternoon, Mr. Abbott, who had been seen arguing with Mr. Adan immediately before his death, was charged by the Manhattan District Attorney's office with murder, and a warrant for his arrest was issued by Judge Jeffrey N. Atlas of Criminal Court. Law enforcement officials said they expected Mr. Abbott to arrive in New York, escorted by Federal marshals, late tomorrow afternoon. He has retain ed Ivan Fisher, a New York criminal defense lawyer.

Home builders, among the leading advocates of the tax-exempt savings certificates created by Congress, appear unlikely to benefit very much from the money that banks will raise from the certificates after they go into effect on Oct.1. Analysts say that very little of the money will be invested directly into home mortgages, although that was one of the the intents of Congress in creating a savings instrument that would provide less costly funds for financial institutions. The analysts see the certificates as being of primary benefit to the balance sheets of the nation's mutual savings banks and savings and loan associations, together known as thrifts. Congress had hoped that the thrift institutions would use the cheaper money from the certificates to finance more mortgages and thus stimulate home construction, now at one of its lowest levels in 35 years. But because much of the flow into the new tax-exempt certificates will merely be transfers into new accounts, bankers forecast, and because the certificates will only be sold for 15 months, the possibility that the money will flow into long-term housing loans is seen as doubtful.

In the News of Music column yesterday, the broadcast date for a complete, 12-hour performance of John Cage's "Empty Words" on WNYC was given incorrectly. The performance will be broadcast tonight starting at 9:30