A mutation of the deadly Delta variant of the coronavirus has sparked an uptrend of Covid-19 cases in eight cities in Indonesia in the last three weeks, but health minister Budi Sadikin does not expect it to cause a serious outbreak similar to that in July.

The new AY.23 mutation originated in Indonesia and shares similarities with the Delta Plus variant that has cropped up in Britain, the minister said at a health webinar over the weekend.

“We are lucky we are past the peak of the Delta wave, hence the people’s immunity is there,” said Budi.

In his presentation slides obtained by the Straits Times on November 15, Budi said AY.23 accounted for about 70 per cent, or 3,288 of the total 4,732 genomes of the positive samples collected from the nation’s 12 genome sequencing test labs.

The eight cities that have recorded an uptrend of new Covid-19 cases are Lebak in Banten province, Sumedang in West Java, Purbalingga and Kendal in Central Java, Tuban in East Java, Teluk Wondama and Fak Fak in West Papua, and Kendari in Southeast Sulawesi.

Other places such as West Jakarta; West Java’s Karawang, home to the automotive sector; and East Java’s Gresik, one of the cement production centres, have seen new cases increasing in the past two weeks.

Many parts of Indonesia, however, have gradually moved towards normalcy after the country managed to bring under control the latest wave of the disease, caused predominantly by the Delta variant, which started after Hari Raya in May.

The seven-day average for infections peaked in mid-July with 50,000 cases daily. The number has plunged to 1,700 in early October, and to 400 today. Death rates have similarly dropped from the seven-day average peak of 1,700 in early August to around 100 in early October, and 16 today.

Indonesia is taking extra efforts to contain the coronavirus to prevent any resurgence, which would prompt stricter movement restrictions that would hurt the economy. It will hold the presidency of the Group of 20 nations in 2022 and host the summit in Bali in the fourth quarter next year.

The Delta variant was first detected in India and reached Indonesia around March. By June, it dominated more than 90 per cent of Covid-19 cases found, according to the government.

“That time, we tightened the restrictions at airports, but the Delta variant entered via a seaport. Learning from that, we are now stepping up checks at five airports, nine seaports and four land entry points,” said Budi.

Most cases of air travellers who tested positive were found at the Soekarno-Hatta International Airport, added Budi. Most infected sea travellers entered the country via Batam seaport, and the majority of infected land travellers came in at Entikong, a border crossing between Indonesia’s West Kalimantan and the Malaysian state of Sarawak.

A three-day mandatory quarantine has been imposed on fully vaccinated foreign visitors from 19 selected countries since November 3. The authorities had cut the length of quarantine from eight to five days in mid-October.