Flights could soon be cancelled if supplies from the Gulf remain blocked, says the International Energy Agency.
Immunisation saved hundreds of thousands of UK lives, but vaccine hesitancy remains an issue.
No 10 says the government is working to ensure "anyone potentially abusing our immigration system is held accountable".
The comments follow a high-profile spat with US President Donald Trump, who called the Pope weak on crime.
Khushal Yousafzai has been opening up to BBC Asian Network about the impact of one day in 2012.