The most significant medical problems affecting survivors of a nuclear war between the United States and the Soviet Union States and the Soviet Union will be infection and the spread of communicable disases, according to a Harvard Medical School Physician writing in the November issue of the New England Journal of Medicine, released today.

Dr. Herbert L. Abrams, Cook Professor of Radiology, said in a news conference Tuesday that 86 million people would die immediately after a 400-megaton attack on "urban and population centers: in the United States, and an additional 50 million fatalities "are anticipated" during the shelter period of several weeks following the attack.

Of the 94 million Americans who would survive beyond the shelter period, 34 million will be severely injured, and for them, "the single most important threat to life, outside of burn and blast injuries, will be infection," Abrams said.

No Mercy

Abrams' study is based on a model of nuclear war used by the Federal Emergency Management Agency in civil defense planning.

Radiation, which, "alters the immune response of man," will be a prime factor in causing infections, and malnutrition, starvation, and dehydaration would also contribute to a "lowered natural resistance" to infections and disease, Abram said.