A spokeswoman for the United Arab Emirates (UAE) state health sector encouraged people in the country to receive a third “booster” dose of the Chinese-made coronavirus vaccine candidate “Sinopharm” on Tuesday, despite the fact that Sinopharm officially requires just two doses.

“As part of the state’s proactive strategy to provide maximum protection for society, the door has been opened for the public to receive an additional supportive dose of Sinopharm vaccine candidate for people who have received the vaccine previously and who have completed more than six months on the second dose,” U.A.E. health sector spokeswoman Dr. Farida Al Hosani said on May 18.

The W.H.O. Strategic Advisory Group of Experts (SAGE) on Immunization recommends just two doses of the Sinopharm product on the official W.H.O. website:

WHO recommends an interval of 3–4 weeks between the first and second dose. If the second dose is administered less than 3 weeks after the first, the dose does not need to be repeated. If administration of the second dose is delayed beyond 4 weeks, it should be given at the earliest possible opportunity. It is recommended that all vaccinated individuals receive two doses.

The UAE’s new campaign advertising a third “supplemental” dose of Sinopharm comes amid increasing doubts about the vaccine candidate’s effectiveness against the Chinese coronavirus. Both Pakistan’s president and prime minister in March contracted the Chinese coronavirus days after publicly receiving Sinopharm, which was developed by the state-run China National Pharmaceutical Group.

The UAE became the first country outside of China to authorize Sinopharm for emergency use on December 9, 2020, despite a lack of public data on the vaccine candidate’s safety and effectiveness at the time. China National Pharmaceutical Group has yet to publish late-stage clinical data on Sinpoharm’s efficacy and safety in scientific journals nearly half a year later. Despite this failure, the Chinese state-run company successfully campaigned for and received, on May 7, emergency use authorization from the World Health Organization (W.H.O.).

“Sinopharm hasn’t published its late-stage test results in scientific journals, so the WHO requested a breakdown of its data, which come mostly from the United Arab Emirates,” the Associated Press (AP) reported at the time.

“(We) came to the conclusion that there is enough evidence of safety and the capacity of the vaccine to prevent severe disease or symptomatic and hospitalized cases up to 79 percent,” Dr. Alejandro Cravioto, who heads the W.H.O. advisory group on immunizations, said on May 7. “The information we have for people over 60 is still very scarce.”

“Previously, a separate group advising WHO on vaccines said it … had a ‘low level of confidence’ in the vaccine’s efficacy for people 60 and over. Its members said they had ‘very low confidence’ in the available data about serious side effects in that age group,” according to the AP.

China’s Center for Disease Control (CDC) warned in April that all Chinese-made coronavirus vaccine candidates, not just the Sinopharm offering, “don’t have very high protection rates.” Reports indicate Chinese officials are hoping to soon import vaccine doses produced by the American company Pfizer and partner BioNTech to supplement its low-quality products.

Sinopharm is an “inactivated” vaccine candidate made using a killed sample of “SARS-CoV-2,” which is the type of coronavirus that causes the disease known as “COVID-19,” or the Chinese coronavirus.

“Most other COVID-19 [Chinese coronavirus] vaccines being used around the world, particularly in the West, are made with newer technologies that instead target the ‘spike’ protein that coats the surface of the coronavirus,” the AP noted in May.