(Bloomberg) -- Visitors to Dubai’s World Expo will now be required to provide Covid vaccination certificates or get tested to enter the event, under new rules issued days after organizers said inoculations weren’t needed.

The Expo is one of the world’s biggest in-person events since the pandemic began and is expected to attract 25 million visits over six months. Visitors will now be required to present proof of a vaccination or a negative PCR test taken within the previous 72 hours, according to reports in the local media.

The move would mark a shift from last week when the organizers said they “encourage” vaccination, but visitors would not be required to provide proof of immunization or a negative PCR test.

The Expo, initially set for October 2020, was meant to attract millions of visitors and provide a boost to the local economy. But as the pandemic hit, halting the global economy, the government postponed the event and reconsidered its targets.

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