The Health Ministry has detected two more polio cases in Sabah involving two children who had never received any immunisation, a month after an infant was diagnosed with the same virus.

A statement issued by the ministry said the two new patients are an 11-year-old boy who lived in Kinabatangan, and an eight-year-old boy in Sandakan.

Both of them, according to the authority, are children of migrants and had not received any vaccination since birth.

The boy from Kinabatangan has had a fever since mid-November and received treatment at a clinic, but was admitted into a hospital on Dec 1 after he claimed of back pain and could not walk.

In the case of the patient from Sandakan, the boy had a fever starting Dec 9, and subsequently lost his ability to walk three days later. He is now still in hospital and has to rely on a ventilator.

"Stool samples from both patients had been sent to the World Health Organisation's Polio Regional Reference Laboratory in Melbourne for tests and genetic sequencing.

"On Jan 9, both children had been confirmed to be positive with the polio virus by the laboratory," the ministry said.

It added that the laboratory tests had also found that the polio virus that infected all three victims had a genetical connection with a polio outbreak that happened in the Philippines last year.

Until the detection of the first polio case in December, which involved a three-month-old Malaysian boy from Tuaran, Malaysia had been free of the disease for 27 years.

Health director-general Dr Noor Hisham Abdullah had in a statement in December said it was confirmed that the baby was suffering from circulating vaccine-derived poliovirus type 1 (cVDPV 1).

According to the Health Ministry, following the detection of the two new cases, they have carried out an investigation at the areas where the two boys were living and conducted checks on 705 people there.

They detected no other polio cases there, while 65 children found to have missed polio immunisation in the areas had been administered a five-in-one (lima serangkai) vaccination.