March 17: Figures showing a global rise in COVID-19 cases could herald a much bigger problem as some countries also report a drop in testing rates, the World Health Organisation (WHO) said on Tuesday, warning nations to remain vigilant against the virus.

According to Reuters, the WHO has stated that COVID-19 cases started to increase around the world last week after more than a month of decline. The news agency reported that lockdowns have been imposed in Asia and China's Jilin province is battling to contain an outbreak.

A combination of factors was causing the increases, including the highly transmissible Omicron variant and its BA.2 sublineage, and the lifting of public health and social measures, Reuters cited WHO as saying.

"These increase are occurring despite reductions in testing in some countries, which means the cases we're seeing are just the tip of the iceberg," Reuters quoted WHO's head Tedros Adhanom Ghebreyesus as saying.

Low vaccination rates in some countries, driven partly by a "huge amount of misinformation" also explained the rise, WHO officials said.

New infections jumped by 8% globally compared to the previous week, with 11 million new cases and just over 43,000 new deaths reported from March 7-13. It is the first rise since the end of January, the news agency further reported.

A number of experts have raised concerns that Europe faces another coronavirus wave, with case rising since the beginning of March in Austria, Germany, Switzerland, the Netherlands, and the United Kingdom.

The WHO's Maria Van Kerkhove reportedly said at the briefing that BA.2 appears to be the most transmissible variant so far. However, there are no signs that it causes more severe disease, and no evidence that any other new variants are driving the rise in cases, according to Reuters.

“The picture in Europe is also not universal. Denmark, for example, saw a brief peak in cases in the first half of February, driven by BA.2, which quickly subsided.”