May 26, 2020 | 7:29am | Updated May 26, 2020 | 9:03am

Countries could see an “immediate second peak” of coronavirus if they reopen too quickly, warned a top World Health Organization official who said the world is still battling the first wave of the disease.

“Right now, we’re not in the second wave,” said Dr. Mike Ryan, a World Health Organization executive director, on Monday. “We’re right in the middle of the first wave globally.

“We’re still very much in a phase where the disease is actually on the way up,” the official told reporters, pointing to South America, South Asia and other areas seeing burgeoning numbers of infections.

Noting how epidemics often come in waves, Ryan said outbreaks could pop up later this year in places where the first wave has subsided.

Mike Ryan, Executive Director of the World Health Organization
Mike Ryan, Executive Director of the World Health OrganizationREUTERS

“When we speak about a second wave classically what we often mean is there will be a first wave of the disease by itself, and then it recurs months later,” he said. “And that may be a reality for many countries in a number of months’ time.”

The WHO warned leaders in Brazil, now the second-most-affected country next to the US with 375,000 confirmed coronavirus cases, to avoid reopening its economy before it can perform enough testing to keep the rapid spread under control.

“Intense” transmission rates in the country mean Brazil should continue some stay-at-home measures, despite the burden on the economy, according to Ryan.

“In these kind of circumstances, there may be no alternative,” he said. “You must continue to do everything you can.”

A travel ban on foreigners coming from Brazil to the US is set to take effect Tuesday, after being moved up from Thursday, the initially planned start date.

Meanwhile, India reported a record single-day jump in new coronavirus cases for the seventh straight day. The country reported 6,535 new infections Tuesday, bringing the tally to 145,380, including 4,167 deaths.

There is no proven treatment or vaccine for the deadly bug. But tests by US biotech company Novavax have begun in Australia in hopes of releasing a proven vaccine this year.

The first phase of the trial is underway, in which 131 volunteers are getting injections to test the vaccine’s effectiveness and safety.

Worldwide, more than 5.5 million coronavirus cases have been reported. The US has seen the greatest number of cases, with more than 1.6 million reported.

With Post wires