Dr Ghebreyesus was accompanied on his second official visit to Pakistan by WHO Regional Director for the Eastern Mediterranean Dr Ahmed Al-Mandhari.
According to media reports, Bill and Melinda Gates foundation President Chris Elias contacted Imran Khan and gave the letter to the PM.
The prime minister's focal person on polio eradication, Babar Atta, had said that the premier told Gates that traces of polio virus had been found in three cities - Karachi, Peshawar and Chaman, a town near the Pak-Afghan border.More news: $500000 Fortnite event to take place at the Australian Open
He said polio vaccination activities are well organized in close collaboration with provinces and are directly overseen by the National, Provincial and Divisional Task Forces.
"The government is determined to implement a transformative social and economic agenda for a "New Pakistan", the prime minister said.
The letter has sought approval from the prime minister for this goal. He also informed the prime minister about WHO's ongoing programmes in Pakistan.More news: Morata move 'very, very complicated', says Sevilla director
Missing children and refusals by parents are the key challenges facing the eradication of polio in Pakistan, World Health Organisation Director General Dr Tedros Adhanom Ghebreyesus said on Tuesday.
He said the WHO had increased its focus on public health, country-level impact and improving people's access to health-related knowledge and information.
The foreign minister said the WHO had been playing a very important role in the health sector of Pakistan. Imran reiterated his commitment to move forward on sustainable development agenda.More news: John Travolta finally embraces natural bald look
As per details, the premier and World Health Organization chief discussed the measures taken to eradicate polio from Pakistan. The foundation will continue to invest in efforts to eradicate polio in Pakistan, the letter read. "Discussions [were] held on steps being taken for polio eradication in Pakistan", spokesperson for the Foreign Office Dr Muhammad Faisal said in a tweet.