The United Arab Emirates is offering people who have shown weak immunity after two doses of the Sinopharm vaccine a third shot of the Chinese jab as booster.

Healthcare authorities have told anyone who fears they are not immune after taking an antibody test after their second dose to return to the centre where they were vaccinated.

“The vast majority of people have taken Sinopharm and it shows a good response,” said a doctor working at a government hospital. “The booster is only needed if you don’t mount an immune response after two jabs.”

A health official told local media last month that a third dose might be needed for a minority shown to have insufficient levels of antibodies in subsequent tests.

The China-manufactured Covid-19 vaccine has driven the UAE’s successful vaccine campaign which has delivered 67 doses per 100 residents, second only to Israel in countries with a sizeable population.

Apart from the UAE, only a handful of nations — including Bahrain, Pakistan, Egypt, Serbia and Hungary — have authorised the use of the Chinese-state backed Sinopharm vaccine amid questions over the transparency of its trial data. The company says the jab has an efficacy rate of 79 per cent in phase 3 trials.

Many of the UAE’s vaccinated residents are now seeking antibody tests three weeks after their second dose to find out whether they have the ability to fight off coronavirus, or need a third shot of the vaccine. A Sinopharm booster is also available for those who had their first dose more than six months ago.

Dr Nawal Al Kaabi, chair of the national Covid-19 clinical management committee, said initial data had suggested that immunity would last for four to six months. She estimated that less than 1 per cent of those vaccinated were not generating enough antibodies to fight off the disease.

“It is not significant at all,” she added.

G42, Sinopharm’s distributor across the Middle East and north Africa, said in a statement: “A select group of people are being administered a third shot to observe the immune system response.”

It said the study was being taken in consultation with Sinopharm and the UAE authorities and that similar studies were taking place with other vaccine developers in other markets.

The UAE government and Sinopharm did not immediately respond to a request for comment.

The UAE has delivered one of the world’s most successful vaccine programmes, with Abu Dhabi and federal authorities deploying Sinopharm across all seven emirates. More than half of the target population has been vaccinated and 70 per cent of the elderly and vulnerable have received the free jab, the health ministry said late on Tuesday.

The UAE has also become a “vaccine destination”, attracting well-connected foreigners who have been able to access Sinopharm and BioNTech/Pfizer vaccines privately.

Dubai, which operates its own health authority, has also been administering the Pfizer and Oxford/AstraZeneca jabs. This month, the Russian Sputnik V was also offered.

Abu Dhabi has deepened its relations with China during the pandemic, sharing information on the virus and collaborating on vaccines and testing.

G42, a private company linked to the Abu Dhabi ruling family, partnered with Sinopharm CNBG to conduct phase 3 trials with 42,000 volunteers across four countries, including the UAE. It plans to start manufacturing the Sinopharm vaccine this year.

The UAE started vaccinating frontline workers in September, before rolling out a nationwide drive in December for Emiratis and residents.

The emirates have diverged in their approach to Covid-19. Oil-rich Abu Dhabi remains closed off with tough restrictions on entry into the capital. Dubai, the region’s tourism and commercial capital, has tried to keep its outward-facing economy as open as possible since emerging from one of the world’s strictest lockdowns last May.

After Dubai welcomed a surge of visitors over the new year holiday period, new cases across the UAE soared to a new peak in late January. The second wave has been declining since March, but new infections per capita remain higher than in the UK and the US.