The Paris 2024 Olympic Games has been dogged by health concerns both before and during its run. The poor air quality in Paris loomed over organisers before the games began with experts scrutinising the pollution levels.

Then, once it had all kicked off, there were numerous cancellations and setbacks due to the poor water quality in the River Seine, where some events were scheduled to take place.  An old foe has since risen its ugly head reminding us that it is very much still around.

Many high-profile athletes have tested positive for Covid-19 at the Paris Olympics, including British swimmer Adam Peaty. He tested positive one day after winning a silver medal in the 100m breaststroke, while Lani Pallister of Team Australia, was too ill to compete and had to pull out of the women's 1500m freestyle.

It comes as the WHO emphasises a need to keep vaccinating those most at risk having noticed a resurgence in positive Covid-19 tests. "Covid-19 is still very much with us. The virus is circulating in all countries," said Maria Van Kerkhove, epidemic and pandemic preparedness and prevention director at the World Health Organisation in a media briefing.

Van Kerkhove warned that wastewater surveillance suggests SARS-CoV-2 circulation is "two to 20 times higher than what is currently being reported." Wastewater can reportedly be used to gather an advanced indication of hospitalisations two or three weeks before. 

"This is significant because the virus continues to evolve and change, which puts us all at risk of a potentially more severe virus that could evade our detection and/or our medical interventions, including vaccination," she said.

The positivity rate around the world is currently just over 10% but the figure is double that in Europe. Van Kerkhove said the recent surge was not typical for respiratory viruses which are more prevalent during the colder months.

"In recent months, regardless of season, many countries have experienced surges of Covid-19. Including at the Olympics, currently, where at least 40 athletes have tested positive," she said. 

"It's not surprising to see athletes being infected, because as I said before, the virus is circulating quite rampantly in other countries." Van Kerkhove also highlighted an "alarming decline" in vaccinations against Covid-19 calling current coverage rates "abysmal."

"The perception that Covid is gone is real... but the virus isn't gone," she concluded.