San Francisco Chronicle; Sunday, April 13, 1998
William Carlsen, Chronicle Staff Writer

The exposure risks appear to be very low, but with more than 1 million needle sticks every year, thousands of female medical workers unknowingly may have been affected over the last several decades. And the discovery underscores the potential dangers from needle stick exposure that still have not been fully explored.

The new discovery involves the Rh factor, or antigen, that coats the surface of red blood cells. When a woman's blood is Rh negative -- not coated with the antigen -- and it comes into contact with coated Rh-positive blood, her blood forms antibodies in reaction. The antibodies stay with her for life.

If she then conceives a fetus that has inherited the Rh-positive factor from its father, the antibodies in her blood during her pregnancy pass through the placenta into the fetus and attack the fetus' blood. If not treated, the fetus suffers severe anemia, which leads to brain retardation or death. "It's definitely an important concern that has to be addressed," said Janine Jagger, a University of Virginia professor and health care safety specialist who first made the connection between the Rh problem and needle sticks.

Her discovery is so recent that no hard data has been collected yet or scientific papers written. Jagger and her staff at the International Health Care Worker Safety Center in Charlottesville, Va., are preparing a research study for publication.

Jagger stumbled on the problem because she is Rh negative and had been tested for the antibodies during several pregnancies.

"I knew that exposure to Rh-positive blood caused childbearing problems," she said. "So I started calling some experts I knew, thinking that of course this had been already considered in light of the needle stick problem.

"I got these long silences. No one had even thought about it."

Jagger and other experts say the critical question is how much blood it would take to trigger the antibody reaction and whether the amount transmitted by a needle stick would be sufficient.

"There's no question that some needle sticks are serious enough to cause it," Jagger explained. "For the majority of needle sticks, it is very unlikely."

Dr. John Bowman, a senior scholar at the University of Manitoba in Canada and a world-renowned expert on the Rh factor, is also cautious. "Obviously, it can happen through a needle stick," he said. "But compared to the transmission of the HIV or hepatitis viruses, the risk is very low." He also pointed out that only 15 percent of the female population has Rh-negative blood, and the other 85 percent who are Rh positive would be completely unaffected.

Jagger said the most likely cases in which the transfer of the Rh factor would occur would be when blood is drawn into a syringe, then accidentally injected into an Rh-negative female medical worker. "We certainly know of such cases," she said.

"For ordinary needle sticks involving syringes used for injections, it's very unlikely there would be a sufficient exposure. But there is a gray zone for other kinds of needle sticks, where the needles are filled with blood, and we just don't know yet where to draw the line."

Jagger said women can be given a safe, inexpensive shot that will stop the Rh antibody reaction. But it must be given within 72 hours to be effective. Jagger said that currently no testing is done to determine the Rh factor or presence of the antibody in medical workers after a needle stick because the problem has never been raised before.

Her study, she said, may prompt health care employers to add the inexpensive tests and the shot, if necessary, to their routine post-exposure care for needle stick victims.

The complications from what is called Rh disease in fetuses are well known because many Rh-negative women have been exposed to Rh-positive blood through transfusions or prior pregnancies when the blood of an Rh-positive fetus has passed into the mother's blood.

Because of the dangers, pregnant women are routinely screened to determine their Rh factor. If the antibody is found, the fetus is closely monitored. The fetus develops severe anemia as the antibody attacks its blood and requires frequent blood sampling and other invasive procedures that may include blood transfusions while in the womb and after birth. A small percentage of fetuses and infants do not survive despite treatment.

DISEASES TRANSMITTED THROUGH NEEDLE STICKS

A wide range of infectious diseases are being transmitted through accidental needle sticks to medical workers, prison personnel and emergency workers like paramedics and firefighters.

The infections can be fatal.

Incompatible blood passed through needle injuries can also result in serious birth complications for pregnant healthcare workers.

THREE MAJOR DISEASES CAN BE TRANSMITTED THROUGH NEEDLESTICKS:

HIV, also known as the AIDS virus

-- Up to 60 health care workers a year contract the virus from needle injuries. The virus attacks its victim's immune system allowing other diseases such as pneumonia and cancer to develop. It was considered fatal but new drugs allow many of the infected to live indefinitely with the virus. There is no vaccine to prevent infection from the virus.

Hepatitis B virus

-- In the 1980's, up to 12,000 workers every year were contracting the virus and as many as 300 were dying. The figure has now fallen to 1,000 a year following widespread availability of the hepatitis B vaccine. The hepatitis virus attacks the liver, causing jaundice, extreme fatigue, abdominal and joint pain, fever and rashes. Chronic hepatitis can result in liver cancer, cirrhosis, coma and death. A three-shot vaccine is extremely effective in preventing infection.

Hepatitus C virus

-- At least 1,000 health care workers a year are infected.

Because the disease has been poorly documented, the number may be many times higher. Symptoms are similar to those of hepatitis B but hepatitis C is far more serious with much higher incidence of fatal liver disease. The virus is the leading cause of liver transplants and no vaccine exists to prevent the infection.

More than 20 other infections can also be transmitted through needle sticks, including:

-- Syphillis, Malaria, Tuberculosis, Streptoccal and Staphyloccal sepsis, Rocky Mountain Spotted fever, Herpes, Hepatitis D and G, Babesiosis, Brucellosis, Leptospirosis, Arboviral infections, Relapsing fever, Creutzfeld-Jakob disease and viral fevers caused by Ebola.

WHY FEMALE WORKERS WITH RH-NEGATIVE BLOOD MAY FACE AN ADDED RISK

At this time, no test is given to detect or monitor a change in Rh factor in new needle stick victims.

1. Needle stick

Nurse with Rh-negative blood comes in contact with Rh-positive blood through accidental needle stick.

2. Blood transfer

Nurse develops antibodies to the Rh-positive blood. These antibodies stay with her for life.

3. Potential dangers during pregnancy

If a health care worker conceives a Rh-positive fetus, her Rh antibodies pass through her placenta into the bloodstream of the growing fetus. The antibodies attack the fetus' blood. If not treated, the fetus may suffer brain damage or it may die. Treatment usually involves transfusions of unsensitized Rh negative blood to the fetus while in the womb or total exchange tranfusions after the baby is born.

Sources: Centers for Disease Control, Occupational Safety and Health Administration, International Health Care Workers Center, ""The Human Body," ""The New Good Housekeeping Family Health and Medical Guide" and Chronicle research

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