Less than 100 suspected SARS cases now remain in Beijing's hospitals, according to vice-director of the Beijing Municipal Health Bureau Liang Wannian.
During the peak of SARS epidemic, about 30 per cent became clinically confirmed cases, but the proportion may decline sharply now, said Liang.
"We still cannot calculate the proportion figure now as the base number is too small,'' he said.
There were 550 cumulative suspected SARS cases in Beijing by 10 am Sunday, according to the Ministry of Health, including the suspected cases in hospitals, those suspected cases that have recovered and the suspected cases who have died, according to Liang.
Meanwhile, nearly all the SARS cases both clinically confirmed and suspected, which were a tiny amount over recent days, are from isolated people who have had close contact with SARS patients, according to the official, who is also an epidemiology and health management expert.
He said that Beijing's designated fever clinics received nearly 2,000 patients every day recently and none turned to be SARS cases.
But he warned that prevention and control measures should not be relaxed as there is still the possibility that SARS cases may come from unidentified sources.
No new case was reported Sunday in Beijing or anywhere on the Chinese mainland, the Ministry of Health announced Sunday.
Beijing Sunday excluded a previously reported clinically confirmed SARS case, which was released on Saturday.
"The decision was made by the expert group after comprehensive re-examination and consultations, which proved that the patient was not infected by SARS,'' Liang said.
He said the correction is a good thing as it reflects rapid action in the diagnosis of SARS patients.
Liang revealed that after the more accurate laboratory test, which is being researched by the Beijing authorities jointly with World Health Organization (WHO), SARS cases will be more quickly and accurately diagnosed.
In another development, the transmission route of SARS in northeastern Beijing's Beiyuan residential area is still not yet known.
"It remains under investigation,'' Liang said.
"It is still too early to say whether it is transmission within community or mere coincidence,'' Liang said.
What is confirmed is that among the 14 SARS patients in the area, three members of a family have infected one another, he said.
It is also suspected that the four people from three families, who lived in the No 15 building, are infected through the windows, which are very near.
Besides them, the buildings of the other seven people are far from each other and the persons are free from contact.
"In a word, I could say in full responsibility that the transmission is not from one person and did not all occur within the community,'' he said.
Liang further stated that the house structure is probably a factor of the transmission but this still requires more proof.
According to Zhang Shutian, an official responsible for the prevention and control work of SARS in Laiguangying Subdistrict, where Beiyuan is located, dozens of people from the community remain in isolation.
Isolated people include those who have close contact with those SARS cases, as well as some of the people who live in the No 15 building, where the largest number of SARS patients live.
"I am so happy to see that since May 26, no new cases have occurred there. It proves that our work is effective,'' she told China Daily.
Among the 14 clinically confirmed SARS cases at Beiyuan, one died, 10 have recovered and left hospital and three people remain in hospital now.