PEOPLE  across the world are being encouraged to donate $7 a dose in a World Health Organization-led push to raise extra funds for the COVAX international COVID-19 vaccine-sharing programme. Launching the "Go Give One" campaign yesterday, the WHO's director-general Tedros Adhanom Ghebreyesus said it would allow anyone who wants to "to play their part in vaccinating the world with a simple donation" and, in time, help end the pandemic. The WHO estimates that $7 would cover the cost of buying and delivering a vaccine dose for someone in a low income country. The campaign also will seek matching funds from…