When the coronavirus vaccine becomes available, medical staff in every country have to get vaccinated first.

In 1918, when the St Marylebone Infirmary in London was under the immense pressure of a Spanish flu outbreak, Dr Basil Hood, the infirmary's medical superintendent, wrote: "Each day the difficulties became more pronounced as the patients increased and the nurses decreased, going down like ninepins themselves." 

In the midst of today's COVID-19 pandemic, a similar scenario is playing out. The outbreak has already killed more than 260 nurses. It is believed that between 90,000 and 200,000 healthcare workers have been infected with the novel coronavirus worldwide.

Faced with an aberrant shortage of medical equipment, health workers from around the globe have struggled to protect themselves from the virus, often forced to use their disposable personal protective equipment (PPE) many days in a row. And that is if PPE is even available in the first place.

In New York City last month nurses were forced to put on rubbish bags for the lack of protective gowns. "It's like something out of the Twilight Zone," one nurse said.

Photos of medical workers from around the world with bruises on their faces after working endless hours battling COVID-19 have been circulating on the internet. And there are other scars which have remained hidden: The crisis is having a devastating effect on the mental health of healthcare workers.

In one Chinese study conducted with medical staff working with COVID-19 patients, 71.5 percent reported distress, 50.4 percent said they had symptoms of depression, 44.6 percent presented symptoms of anxiety, and 34 percent suffered from insomnia.

Health workers have gone to extreme lengths to protect the rest of the population and they have been lauded as heroes for their response to the coronavirus pandemic. People have clapped, banged pots, draped signs at their windows to thank doctors, nurses, hospital and care homes staff, and any other "essential worker" that has kept our health systems running, while COVID-19 hit with all its thunderous power.

While there has been a renewed appreciation of the role of health personnel in society, this is far from enough. The long-term safety of health workers across the world must be guaranteed. It is crucial that we give our modern superheroes more than praise and messages of gratitude. We have to make sure they are properly protected.

Currently, there is a global effort to develop a vaccine for the novel coronavirus, which is estimated to take 12 to 18 months. Once it becomes available, however, it is clear that there will not be enough supply for the entire world, at least in the short term.

Indeed, it will take at least 12 months to vaccinate the world, starting from the moment a vaccine is approved for use. In past pandemics, like the H1N1 more than a decade ago, wealthy nations sought to monopolise the global vaccine supply and hoarded large amounts of it. Some, like Australia, even refused to export it in the beginning.

While there have been pledges for a fair distribution of the vaccine from the European Union and other institutions, we know there is little chance of this actually happening. Therefore, a provisional solution must then be found - one that recognises populations that need to be given priority.

A functioning health system is the best tool that countries have to tackle, or at least slow down, the pandemic. A functioning health system depends for a vast majority of its operations on people: nurses, doctors, cleaners, cooks, technicians, and any other support personnel. All of these people face a tremendous risk of contagion and are at a higher risk of fatal outcomes from the COVID-19 disease.

These are the people we need to ensure are vaccinated first in every country without exception. This will not only guarantee that health systems continue to function well and are able to treat infections, but it will also help run a smoother vaccination process for the rest of the world's population.

This is the reason why today, on International Nurses Day, medical workers from all over the world are joining a citizens' call to demand that the World Health Organization (WHO) ensures priority vaccination for health workers across the globe, regardless of their nationality. Global cooperation is needed more than ever and for that to happen WHO member states have to come to a consensus.

Now is the time to show our real gratitude to medical workers by pressuring our governments to commit to vaccinating medical staff first, not just in our countries but across the world. We need to make sure there is an international agreement on this and no exceptions are made.

On May 18, the World Health Assembly will convene. They must hear the call for solidarity of the people of the world, demanding that health workers receive the vaccine first. No country, no health worker should be left behind. It is time for the WHO and world governments to step up and protect the "angels of COVID-19". Stand by them, join the call.