World leaders must fund a Covid-19 vaccine plan before it's too late for millions | Gro Harlem Brundtland and Elizabeth Cousens

This week's Global Vaccine Summit comes at a crucial point in history. Governments must not miss their chance to save lives

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• Gro Harlem Brundtland is former director-general of the World Health Organization
• Elizabeth Cousens is president of the UN Foundation

Google any list of the most successful public health interventions of this century or the last, and vaccines will be at the very top. Infectious diseases such as smallpox, measles, diphtheria and pertussis (whooping cough) were once prevalent and killed indiscriminately. Smallpox is now eradicated, polio is on its way out, and measles, diphtheria, pertussis and a wide range of other preventable diseases have been decimated in places where proven vaccines are both affordable and accessible.

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