GENEVA, Jan. 29 (Xinhua) -- The chief of the World Health Organization (WHO) said on Friday that vaccines are now giving a window of opportunity to bring the COVID-19 pandemic under control, but they may also exacerbate the inequalities in distribution across the globe.

Speaking at a press briefing, WHO Director-General Tedros Adhanom Ghebreyesus urged the world not to squander another window of opportunity to curb the pandemic.

"A year ago, I said the world had a 'window of opportunity' to prevent widespread transmission of this new virus." Tedros was referring to a time when there were fewer than 100 COVID-19 cases and no deaths outside China. "This week, we reached 100 million reported cases. More cases have been reported in the past two weeks than during the first six months of the pandemic."

"Vaccine nationalism might serve short-term political goals. But it's ultimately short-sighted and self-defeating," Tedros said. "When a village is on fire, it makes no sense for a small group of people to hoard all the extinguishers to defend their own houses."

Since vaccines are a limited resource, WHO has repeatedly called for their effective and fair use. "That's why I have challenged government and industry leaders to work together to ensure that in the first 100 days of 2021, vaccination of health workers and older people is underway in all countries," Tedros said.

He further called on people in countries that are now rolling out vaccines to use their voice to advocate for their government to share doses. Health and care workers have been on the frontlines of the pandemic and paid an extremely high price in this pandemic.

"Now it's time to show our love and appreciation for health workers by making sure all health workers are vaccinated," he said.