Children in Israel aged five to 11 at risk of serious health complications can be vaccinated against Covid-19 as of August 1, Israeli health officials said Wednesday.

The Israeli health ministry gave the green light for the vaccinations to children who are "at significant risk of serious illness or death" from coronavirus.

"This is a special authorisation, and each vaccination will be studied on a case-by-case basis," a ministry spokesperson told AFP on Wednesday.

The health ministry on Tuesday issued a list of medical problems where a vaccination was advised.

They include children with brain, heart or lung problems, severe immunosuppression, sickle cell anaemia, pulmonary hypertension and severe obesity.

They will be offered a Pfizer/BioNTech dose of 0.1 millilitre, three times less than the standard vaccine.

Last month, health officials extended vaccination to children aged 12 to 16.

About 55 percent of Israel's population has been double vaccinated with Pfizer-BioNTech, thanks to a massive campaign launched in late December after an agreement with the pharmaceutical giant.

Israel's digitised medical databases allowed for rapid large-scale studies.

Its initial vaccine rollout of the jab was among the world's fastest, delivering two doses of the vaccine to more than 55 percent of the population.

Case numbers dropped dramatically, and in early June Israel eased many restrictions.

But soon after, as cases rose, the health ministry reimposed a requirement for masks to be worn in enclosed public places.

The authorities have also announced a partial return to the "health pass" programme, where all events with more than 100 participants entry will be restricted to people who have been vaccinated, recovered from the virus or have had a recent negative test.