As the Delta variant continues its global surge, experts are questioning whether the long-held goal of achieving herd immunity from Covid-19 through vaccination is still viable.

Herd immunity is achieved when a certain threshold of the global population has either been inoculated against a pathogen or has recovered from infection.

As if her cancer treatment was not already agonizing enough, Rita is now wracked with worry about the medication she needs as Lebanon's crippling economic crisis sparks drug shortages.

"The treatment is like fire shooting through your body," the 53-year-old patient told AFP, asking that her real name not be given. "But now on top of that, we have to go hunting for the drugs."

Fatigue and shortness of breath still afflict many patients a year after their hospitalization for Covid-19, according to a new Chinese study calling for a better understanding of the pandemic's long-term health effects.

Around half of patients discharged from hospital for Covid still suffer from at least one persistent symptom -- most often fatigue or muscle weakness -- after 12 months, said the study published in British medical journal The Lancet Friday.

The international scientists dispatched to China by the World Health Organization to find out where the coronavirus came from said Wednesday the search has stalled and warned that the window of opportunity for solving the mystery is "closing fast."

Meanwhile, a U.S. intelligence review ordered up by President Joe Biden proved inconclusive about the virus's origin, including whether it jumped from an animal to a human or escaped from a Chinese lab, The Washington Post reported Wednesday.

"Vaccine passports" are digital or paper documents that show you were vaccinated against COVID-19, and could help you get into a growing number of places.

What they look like and why you might want one depend on where you live, but more private venues, workplaces and governments are requiring proof of vaccination in public settings.

Japan suspended use of about 1.63 million doses of Moderna vaccine Thursday after contamination was found in unused vials, raising concern of a supply shortage as the country tries to accelerate vaccinations amid a COVID-19 surge.

The health ministry said contamination was reported from multiple vaccination sites. Some doses might have been administered, but no adverse health effects have been reported so far, officials said.

Japan was set to expand its coronavirus state of emergency for a second week in a row Wednesday, adding several more prefectures as a surge in infections fueled by the delta variant strains the country's health care system.

The government last week extended the state of emergency until Sept. 12 and expanded the areas covered to 13 prefectures from six including Tokyo. Sixteen other prefectures are currently under quasi-emergency status.

France's health watchdog on Tuesday recommended a third dose of the Covid-19 vaccine for people aged over 65 or considered at risk of developing serious forms of the disease.

The advice from the HAS watchdog was for people who had already received two vaccine doses, who will now be offered an mRNA vaccine such as the ones produced by Pfizer or Moderna, which France has ample supply of. 

What does full approval of Pfizer's COVID-19 vaccine mean?

It means Pfizer's shot for people 16 and older has now undergone the same rigorous testing and regulatory review as dozens of other long-established vaccines.

China reported no new domestic coronavirus cases Monday, and Beijing appears poised to bring to heel the pandemic's most serious resurgence in months -- driven by the highly contagious Delta variant -- with mass testing and targeted lockdowns.

The latest outbreak, which began in mid-July when cleaners at a Nanjing airport tested positive, is the most severe since Covid-19 first surfaced in the central city of Wuhan.