Bay Area AIDS Rate for Women, Babies Higher

AIDS virus infections in childbearing women and newborns in California are twice as common in the San Francisco Bay Area as in Los Angeles County and more than four times as common in blacks as in whites and Latinos, the state Department of Health Services said Tuesday.

The study also confirms that AIDS virus infection rates for mothers and newborns are much lower in all areas of California than rates found in other states with large numbers of AIDS cases, including New York, New Jersey and Florida.

Anonymous testing of blood samples taken from all babies born in California during July, 1988, showed that one in every 610 women giving birth in the San Francisco Bay Area was infected with the human immunodeficiency virus.

In Los Angeles County, the rate of HIV infection was one in every 1,201 mothers, which was similar to the statewide rate of one in every 1,225 mothers. Outside of San Francisco and Los Angeles County, the infection rate was one in every 1,813 mothers.

When compared to congenital syphilis, another serious infectious disease afflicting newborns, HIV infection remains relatively uncommon in Los Angeles County. About one of every 400 infants born in 1988 had syphilis, according to county statistics.

HIV “is currently at a low level (in childbearing women and newborns),” said Dr. Peter Kerndt, the medical director of the AIDS epidemiology program in the county Department of Health Services. “Screening and prevention programs will be most effective while the number of infections is low.”

By comparison, public health officials have documented HIV infection rates as high as one in 77 mothers in New York City and about one in 200 mothers in New Jersey and Florida.

The state also found that one of every 374 black women giving birth was infected with HIV, compared to a rate of one in 1,697 for white women and one in 1,954 for Latino women. The infection rate in Latinos was lower than anticipated, according to Frank Capell, the state Office of AIDS epidemiologist who coordinated the study.

Drug Users

The spread of HIV to childbearing women is primarily thought to occur through intravenous drug use and sexual transmission to women who are the sexual partners of intravenous drug users or bisexual men. Presumably because these modes of transmission are more common in non-whites, most studies have found that HIV infection rates are higher in minorities than in whites.

“This pattern is pretty much what we were expecting,” Capell said. “We thought the infection rates would parallel those we have seen for AIDS cases among intravenous drug users.”

Among intravenous drug users, HIV infections are more common on the East Coast than on the West Coast. Within California, other studies have shown that the infections are more common among intravenous drug users in the San Francisco Bay Area than in Los Angeles County or other areas.

A positive AIDS antibody test on a baby indicates that its mother is infected with HIV but does not necessarily mean that the baby is also infected. Current evidence suggests that only about one-third of the babies who test positive are carrying the virus. The other babies test positive because they receive antibody proteins from their mother, which are subsequently shed over a period of several months.

In total, there were 35 positive HIV tests among the 42,886 mothers who gave birth in California last July, after the data was corrected for such factors as duplicate tests and twin births. State officials cautioned that they did not know the race of 20% of the infected women.

In a related study, Los Angeles County health officials found three infected mothers in tests of 8,533 blood specimens from babies born at four county hospitals in the fall of 1988, Kerndt said. The infection rate--about one in 2,850 mothers--was less than half the rate found for Los Angeles County in the state study.

Kerndt said the difference probably reflected the fact that a high percentage of the babies tested in the county hospitals were Latino and a low percentage black. Latino mothers appear to have a much lower HIV infection rate than black mothers.