Local health officials said here tonight that a dozen patients who had seemed to recover from SARS became ill again after leaving the hospital.
In some cases, the illness returned more than two weeks after discharge, according to a medical expert here who refused to be quoted by name. It is not clear whether the patients contracted the infection a second time, or simply became ill with the same virus after seeming to recover.
Six of the patients are still hospitalized, their condition described as ”stable and good” by the Hong Kong Hospital Authority, while the rest have been discharged for a second time. But the relapses, the first reported since the epidemic broke out in China last fall, raise unsettling questions on the disease, about which much is still unknown.
The relapses are also another sign of the critical need for doctors to develop a diagnostic test for SARS, as Hong Kong hospitals have been releasing patients who no longer show symptoms even though the hospitals have no way to determine whether the patients still have the virus in their bodies.
Such a test would allow epidemiologists to conduct studies to determine, among other things, how long someone infected with SARS could shed the virus. A test might also help determine whether infection with the virus confers long-term immunity or whether individuals are vulnerable to a second attack.
The relapses may mean that patients can still transmit SARS even when they are no longer thought to be infectious. If so, that raises the possibility that transmission might recur in countries where officials have said the outbreak is over.
Less ominously, the relapses could be a complication of treatment, perhaps from the use of steroids that so suppressed the patients’ immune systems that they did not have a chance to develop a strong enough immune defense against SARS.
Hong Kong officials said nothing about these possibilities tonight.
The World Health Organization said today that it had not yet received reports of the relapses. Dr. Mark Salter, a medical officer with the agency, said it was monitoring the nearly 2,500 SARS patients worldwide who have been discharged from hospitals and had seen no reports of relapses or recurrences.
If relapses are occurring, Dr. Salter said, ”we would be concerned.”
Dr. Julie L. Gerberding, director of the Centers for Disease Control and Prevention in Atlanta, said in an interview today that she was aware of the reported relapses but had no details and could not interpret the phenomenon.
In an ideal world, she said, scientists would try to find out whether the SARS virus was confirmed in the 12 patients when they were first hospitalized and whether it could still be identified after their relapses, or whether the patients had developed one of many respiratory ailments other than SARS.
The medical expert in Hong Kong said the 12 patients were of a range of ages, and were not only the elderly, who have had many of the most serious cases and have had the highest mortality rates from the disease.
Many SARS patients in Hong Kong are prescribed continuing doses of steroids after they are discharged from hospital. Doctors here are increasingly concerned that heavy doses of steroids may be suppressing the symptoms of the disease without getting rid of the virus, the expert said.
Dr. Salter said the W.H.O. was accumulating a significant amount of evidence to suggest that the major SARS symptoms — fever, cough and shortness of breath — are caused by a patient’s immunological response to the virus. Doctors in Hong Kong have reported that many patients treated with steroids and the antiviral drug ribavirin improve, he said.
Still, he added: ”We don’t have systematically collected evidence, but we do know that stopping the therapy early can actually exacerbate the symptoms. At the moment, the doctors in Hong Kong are unsure as to the timing required to gain the maximum benefit from using the ribavirin-steroid therapy.”
None of the relapses or recurrences in Hong Kong have occurred among SARS patients hospitalized in the first wave of infections, when doctors tended to delay prescribing steroids until a patient’s pneumonia worsened. The delay might have allowed enough time for a patient’s immune system to begin fighting off the SARS virus before steroids began suppressing the immune defenses.
Health officials are now trying to review the patients’ charts to determine whether steroid therapy in the earliest stage of infection played a role in relapses among patients hospitalized after the first wave.
The number of relapses so far is small — just 12 of the 791 patients discharged from hospitals in Hong Kong, including 39 today. (Forty-five percent of the 1,432 surviving SARS patients, or 641, remain hospitalized.)
Despite the relapses, the pneumonia wards here are slowly emptying as the number of patients who recover or die each day has been exceeding the number of new cases for the last two weeks. There were 7 deaths here today, bringing the total to 157, and 17 new cases, bringing the total number of cases over the last two months to 1,589.
Worldwide, 28 countries and Hong Kong have reported 5,663 SARS cases, including 372 deaths, a death rate of 6.6 percent. Of the 5,291 survivors, 2,470, or 47 percent, have been discharged.
The death rate has varied considerably among countries. Inexplicably, according to Dr. Salter of the W.H.O., ”we seem to be seeing a significantly higher death rate in areas where there are more advanced forms of health care,” like Singapore and Canada, compared with countries with less-developed health systems.