SINGAPORE — As more Zika cases emerge outside the current three geographical clusters, the Ministry of Health (MOH) tweaked its battle plan on Monday (Sept 5) by announcing subsidised tests for the virus for all Singaporeans and permanent residents, regardless of where one lives, works or studies.

Sixteen new cases were found as of noon yesterday — bringing the number of locally-transmitted cases to 258 — with four of these not linked to the Aljunied Crescent/Sims Drive/Kallang Way/Paya Lebar Way, Bedok North Avenue 3 and Joo Seng Road clusters.

From Wednesday, subsidised patients need only pay S$60 for Zika tests at public healthcare institutions. This is provided they have fever, rash, and one other symptom of joint pain, muscle pain, red eyes or headache. Private patients or those who visit private clinics or hospitals will pay the full S$150.

Pregnant women with symptoms or those with male partners who are Zika-positive will continue to get free tests everywhere. Mothers-to-be who wish to be tested regardless will pay a subsidised rate of S$60 at public healthcare institutions.

Doctors will continue to make the call for patients, pregnant or not, on whether testing for Zika is necessary, said the MOH. Patients who need the test but cannot afford it can approach their medical social worker for assistance, such as from Medifund, it added.

In a statement, the MOH said its considerations for testing hitherto were based on the assumption that most cases came from the affected areas. Hence, the free tests for those who live, work or study in these locations, while others pay the full charges.  “However, as more cases are found in other parts of Singapore, testing will no longer be focused on the clusters only, and we will provide a subsidy for the test by the public sector laboratories,” it said.

From Tuesday, the MOH will also no longer require suspected Zika cases to be isolated while waiting for test results. Confirmed patients will also not be required to be hospitalised unless medically necessary. They can return home to await their test results.

“As more cases emerge, there is evidence that there is transmission in the community with the presence of infected mosquitoes. Furthermore, most of the patients do not display symptoms. Therefore isolation of patients with symptoms will have limited effect,” said the MOH.

Elaborating on the change in an exclusive interview with Channel NewsAsia yesterday, Health Minister Gan Kim Yong said when the Zika cluster was first discovered, the MOH was not certain of the extent and whether there was already large-scale transmission. Therefore, it was important for them to isolate patients then to prevent further spread even as investigations were carried out, he said.

The ministry was also not sure whether the Zika cases in Singapore were likely to have very severe symptoms that will cause medical issues, so it decided to hospitalise them first, he added. Given that isolated cases have emerged in other parts of Singapore, Mr Gan said his ministry has to work on the basis that local transmission has spread outside the affected areas.

“Also bearing in mind that there are 80 per cent of our infected patients do not have symptoms and therefore they are not treated by our doctors. Just isolating 20 per cent of our symptomatic patients has very limited effect,” he added. “Therefore, isolation will no longer be very effective.”

Commenting on the move, Dr Leong Hoe Nam, an infectious disease specialist at Mount Elizabeth Novena Hospital, said: “We have lost the opportunity to control the virus. In that case, why waste resources on isolation when we can actually (use) the resources to kill the mosquitoes?”

He added that a person may have the Zika virus in his/her blood for seven to 10 days before the onset of the fever, “so isolating after the onset of fever doesn’t make a lot of sense”.

Dr Wong Sin Yew, an infectious diseases physician at Gleneagles Hospital said patients with a Zika infection usually have the virus circulating in their blood for three to five days. “This is the period that they may be infectious when a mosquito bites them,” he said.

The need for isolation depends on risk assessment and isolating such cases will have limited effects, he added. “The patients should continue to rest at home, preferably in an air-conditioned room while awaiting for the results of their tests,” he added.