A health expert has warned that the world is still in the midst of the “first wave” of the coronavirus pandemic.

World Health Organisation (WHO) executive director Dr Mike Ryan warned that the risks of reigniting coronavirus outbreaks are complicating efforts to fend off further misery for the many millions who have lost their jobs.

Dr Ryan said: “Right now, we’re not in the second wave. We’re right in the middle of the first wave globally.

Coronavirus graphic
(PA Graphics)

“We’re still very much in a phase where the disease is actually on the way up.”

Dr Ryan pointed to South America, South Asia and other areas where the number of infections is still on the rise.

Mindful of the risks, Americans settled for small processions and online tributes instead of parades on Monday as the US observed Memorial Day in the shadow of the pandemic.

A US travel ban is due to take effect on Tuesday for foreigners coming from Brazil, where the virus is raging through communities with no signs of abating.

The ban, which was originally to take effect on Thursday, was brought forward. It does not apply to US citizens.

Underlining the challenge of containing outbreaks of a virus for which there is not yet a vaccine or proven treatment, India reported a record single-day jump in new cases for the seventh straight day.

The country reported 6,535 new infections on Tuesday, raising its total to 145,380, including 4,167 deaths.

Most of India’s cases are concentrated in the western states of Maharashtra, home to the financial hub Mumbai, and Gujarat. The numbers have also climbed in some of India’s poorest states in the east as migrant workers stranded by lockdowns have returned to their native villages from India’s largest cities.

India has nonetheless been easing restrictions. Domestic flights resumed on Monday after a two-month hiatus, though at only a fraction of normal traffic levels.

Australia’s prime minister said that international travel could resume with New Zealand before Australians are allowed to fly interstate, if cautious state leaders refuse to reopen their borders.

Scott Morrison said he had spoken with his New Zealand counterpart, Jacinda Ardern, about resuming regular travel between the near-neighbours, which have shared similar success in slowing the coronavirus spread, though not eliminating new cases altogether.

Drive-in movie theatre
Movie end credits roll at the parking lot of the Carrasco International Airport after it was converted into a drive-in cinema, on the outskirts of Montevideo, Uruguay (AP)

Tests by a US biotechnology company, Novavax, have begun in Australia with hopes of releasing a proven vaccine this year.

A Novavax executive said 131 volunteers were getting injections in the first phase of the trial to test the vaccine’s safety and effectiveness.

Novovax expects the results of the Australian trial to be known in July.

About a dozen experimental vaccines are in early stages of testing or poised to start, and it is not clear whether any will prove safe and effective. However, they use different methods and technologies, increasing the odds that one might succeed.

Novovax’s research chief, Dr Gregory Glenn, said: “We are in parallel making doses, making vaccine in anticipation that we’ll be able to show it’s working and be able to start deploying it by the end of this year.”

Some restrictions on public gatherings, shorter hours for many businesses and other precautions are still in place in most countries.

South Korea has begun requiring people to wear masks on public transport and while using taxis.

The country, once a major epicentre of outbreaks, is tracing dozens of infections linked to nightclubs and other entertainment venues as it prepares for 2.4 million students to return to school on Wednesday.

People in South Korea, like in much of Asia, have generally been wearing masks in public settings anyway, without reports of any major disruptions.

Despite hopes that the so-called “first wave” of the pandemic may be waning, Dr Ryan, the WHO official, warned that future “spikes” of outbreaks may mean the first wave is not over.

With infections surging in South America, the WHO warned Brazil’s leaders against reopening its economy before it can perform enough testing to control the spread of the pandemic.

“Intense” transmission rates mean Brazil should retain some stay-at-home measures despite the economic hardships, Dr Ryan told reporters.

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