"The spread of this virus continues, if you see 160 out of 193 WHO member states now have cases, so we are nearing almost 100 percent but not quite yet," said Gregory Hartl, spokesman for the WHO.
Hartl added that the A(H1N1) virus, which the WHO declared a pandemic in June, has resulted in around 800 deaths.
However, he said it was not possible to give a death rate for the virus, given that "we don't have the exact numerator or denominator."
The WHO late last week stopped issuing figures of infected people worldwide. It said however, that it was continuing to watch for the virus's appearance in new territories.
Meanwhile, Hartl said there remained many unknowns about the virus.
"We don't know how the virus will change going forward," he said.
Another unknown is how the virus would behave in the northern hemisphere's winter, given that it was uncovered only during springtime in the north, he added.