Geneva, Dec 5 The Covid-19 pandemic has not settled down into a predictable pattern, as the situation of transmission and cases in different countries varies a lot, said an expert from World Health Organization (WHO), noting there's no one-size-fits-all solution globally.

Speaking at a virtual press conference on Friday, Mike Ryan, Executive Director of the WHO's Health Emergencies Program, cautioned that "vaccines do not equal zero Covid" and that vaccines and vaccination "will only add a major powerful tool to the toolkit we have now", reports Xinhua news agency.

"That's why countries, particularly those still suffering from rather heavy Covid-19 transmission, really need to sustain the effort and measures to control and bring the number of cases down," he said.

According to the WHO expert, there could be basically two phases for the next six months: the first is controlling and reducing deaths and severe diseases, and the second, controlling the actual transmission of the disease.

Meanwhile, Maria Van Kerkhove, technical lead on Covid-19 response at the WHO Health Emergencies Program, also made it clear that the next six months is going to be difficult but hopeful, and requires patience from all.

She called for strict adherence and vigilance from all by making modifications to their behaviour to deal with the "new normal" until the pandemic is over.

For countries that have brought transmission down, such as many countries across Europe, she urged them to make sure that it stays low, instead of turning back to the situations in spring and keeping switching back and forth between lockdowns and opening-ups.

According to WHO Director-General Tedros Adhanom Ghebreyesus, the pandemic still has a long way to go and decisions made by leaders and citizens in the coming days will determine both the course of the virus in the short term and when this global health criris will ultimately end.

The development comes as the overall number of global coronavirus cases has topped 65.7 million, while the deaths have surged to more than 1.51 million, according to the Johns Hopkins University.

In its latest update on Saturday, the University's Center for Systems Science and Engineering (CSSE) revealed that the current global caseload and death toll stood at 65,771,488 and 1,516,035, respectively.

The US is the worst-hit country with the world's highest number of cases and deaths at 14,343,430 and 278,605, respectively, according to the CSSE.

WHO calls for sustained efforts to control Covid-19 transmission