Many countries around the world are seeing surges in COVID-19 cases, but experts say this isn't a second wave - it is still very much the first.

The picture changes across the globe. In the worst-hit Asian and European countries cases have been slowing down - but not in large parts of the Americas, including the U.S. and Brazil, as well as some other countries, such as India.

The head of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus warned earlier this week that the virus showed no signs of slowing down. 

Despite this, the U.S. has continued to press on with easing restrictions while other countries, including the UK, have opened up, both internally and externally, relaxing rules for foreigners to visit. 

Scientists are worried the containment achieved in lockdown could be rapidly undone because of such moves. 

Bharat Pankhania, an expert in communicable disease control from the University of Exeter Medical School, told CGTN Europe's RAZOR program that in the UK "the number of cases in the community has dropped, which is good, but it hasn't carried on dropping. It has plateaued." 

Pankhania warns that the UK coming out of lockdown too soon could eradicate the gains from "the hardship, the pain of the lockdown."

"This can be undone very, very quickly. It's a very fragile achievement to have brought the case numbers down. It is fragile."

The effects of easing lockdown too quickly can be seen in the U.S., the world's worst-hit country with more than three million cases and 131,000 deaths. 

"This really is our first wave. So a lot of the reason we're seeing these increasing cases is because we never really fully contained what was going on initially," explains Krutika Kuppalli, an infectious disease physician in the U.S. "And so we opened up too quickly. And now we're seeing the after-effects of that. We're seeing cases go up. We're seeing health care systems becoming overwhelmed again." 

Kuppalli has advice for those countries fighting the virus, "the mainstay of any infectious outbreak is being able to test, being able to trace and then being able to effectively isolate and quarantine."

"And that's really what we need to be able to do in order to have a good, robust response, not just here, but all over the world."

Video editor: Sam Cordell