Yet weather is becoming more extreme and unpredictable."

VOA: special.2009.11.23

She says people must keep up their guard against the virus, which is unpredictable and could change into a far more dangerous form.

VOA: standard.2009.12.29

She says the onset of maternal complications is unpredictable, and the response is often slowed by what health experts call "the three delays".

VOA: standard.2009.11.10

World Health Organization Director-General Margaret Chan said the alert level was stepped up because influenza viruses are unpredictable and can spread quickly around the world.

VOA: standard.2009.04.29

"Influenza is unpredictable," There is no way to determine how it is going to react among any one person or group of people, so for those reasons, people cannot really account for what is going to happen if they go into a situation with the intention of getting H1N1."

VOA: standard.2009.12.18