More than 3,000 persons died during the past month of influena or its complications in the United States, the federal Center for Disease Control reported yesterday.

Thus far this winter, the death rate is about 50 percent higher than that expected, but it remains low compared to the 20,000 flu deaths during the spring of 1976.

All of the deaths have been attributed to the A-Texas and A-Victoria viruses, which have caused flu outbreaks all over the country. There have not been any deaths attributed to Russian flu, which has just made its appearance with about a half dozen outbreaks in various parts of the country, including one at the U.S. Naval Academy in Annapolis, and two cases in District.

District officials reported yesterday that between 50 and 60 percent of the residents of Cedar Knoll and Oak Hill, the city's two juvenile detention failities in Laurel, have contracted a flu-like illness whose symtoms are the same as those of the Russian flu -- dry cough, headache, body aches, muscle aches, fever and some abdominal pain.

Health officials have taken throat cultures and blood samples from some of the residents, but will not know until next week what type of virus has struck the institutions.

Dr. Martin Levy, the city's epidemiologist, said yesterday that he has "the feeling some schools will probably have a 50 percent attack rate."

Absenteeism already is high in District schools as a result of the A-Texas presence was confirmed in two children treated at the Children's Hospital National Medical Center.

Those most vulnerable to the Russian flu an HINI virus known as A/USSR/77, are persons 24 or younger. Persons in the 25-to-50 age range probably were exposed to an HINI virus in the 1947 to 1957 period, and thus have antibodies to protect them from further infection.

Those over 50 have little immunity because they were not in the prime age group when the virus last struck, but those most likely to contract the disease are younger persons, more likely to be in close contact with one another in schools, colleges and offices.

There is no Russian flu vaccine available although one is being developed.

Testing of a vaccine is expected to begin next month.