Helping to lead a mass trial for a Chinese-made Covid-19 vaccine in Pakistan, a country where anti-vaccine sentiment can turn lethal and conspiracy theories are endemic, Dr Mohsin Ali has heard all kind of questions from anxious, prospective volunteers.

"Is this going to take away my reproductive ability? Is this going to kill me? Is there any 5G chip in this? And, is there a conspiracy to control people en masse?” he said, recounting the sometimes bizarre doubts clouding people's minds.

“I get many questions like this," he told Reuters at Islamabad's Shifa International Hospital, before adding: “I try to answer them with logic and on the level of the individual asking them. Some still refuse.”

The hospital is one of a number in Pakistan where phase III trials are underway for Chinese vaccine developer CanSino Biologics' Ad5-nCoV candidate.

The government last week announced it had begun the vaccine procurement process, though it has not said whether it will purchase CanSino's candidate or an alternative.

Worryingly, a Gallup Pakistan poll conducted last month showed 37 per cent of Pakistanis would not get a vaccine once one became available.

"Given the history of vaccine resistance, this is an alarming number and not just for Pakistan but also for the world, which depends on universal vaccine coverage to control spread," Bilal Gilani, the pollster's executive director, said.

Countering anti-vaccine sentiments is a worldwide problem, but in Pakistan it is more dangerous than almost anywhere else.

Dozens of people have been killed in attacks on polio vaccination teams over the years, and the fear and mistrust that spawns such violence has made Pakistan one of two countries, including neighbouring Afghanistan, where the crippling disease has still to be eradicated.

Several times every year, polio vaccination drives aim to inoculate millions of children, but in some areas they are often met with refusals from parents who believe conspiracy theories about the vaccine.

In more volatile parts of the country, Islamist militancy played a role in attacks on polio immunisation teams, notably after a doctor was accused of running a fake vaccination campaign to help the US Central Intelligence Agency track down Osama bin Laden in Pakistan in 2011.

Disbelief

Yet the dangers of polio have been well known for decades, whereas Covid-19 is a new disease, and authorities have struggled to communicate the urgent need to stamp it out.

“Many people still don't believe it is a real disease,” said Tauqeer Hussain Mallhi, an assistant professor at Al-Jawf University, in Sakakah, Saudi Arabia, who studies vaccine effectiveness in Pakistan.

A national lockdown was quickly abandoned a few weeks into the virus' spread as too many of Pakistan's more than 207 million people were economically vulnerable, and social distancing remained difficult as the public continued to gather in markets and mosques.

Infection numbers have continued their morbid ascent with 2,885 new cases and 89 deaths reported on Monday — taking the total infections to over 423,000 and fatalities close to 8,500. Experts say Pakistan is only doing a fraction of the testing it should be doing.

Cleric Qibla Ayaz, the head of the Council of Islamic Ideology, which advises the government on social and legal issues, said many of the conspiracy theories about Covid-19 are coming from Western countries, spread by social media.

“For now, the majority of scholars have said the vaccine and other treatments are important [...] but there are always extremists as there are with polio,” Ayaz told Reuters.

“Given the kind of 'Westphobia' we have in Pakistan, it might be better to obtain a vaccine from Russia or China, instead of the US or UK.”