Their "invaluable” work is part of support services, amounting to 1,200 hours a day, being provided by the health and first aid charity since the outbreak of the virus.
In April, the volunteers, all qualified first aiders and advanced first aiders, received additional training from St John and the University Hospitals of North Midlands NHS Trust (UHNM) in how to care for patients during the pandemic.
Volunteers have helped out at the Royal Stoke and County Hospital in Stafford.
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Claire Tooth, matron for emergency medicine, said: “Our volunteers provide support with patient care needs, nutrition, portering, taking observations, scanning notes and preparing patients for transfer.
“They have been absolutely invaluable at this unprecedented time and they have really integrated into the team with ease and taken to every task that they have been asked to do.
"Learning on the job in a very fast-paced environment can be difficult, but they have all clearly found it extremely beneficial and always work with a smile on their face.”
Keele University student and St John volunteer Erin Sohnrey had to cancel plans to celebrate her 21st birthday and decided to work at the hospital instead.
She said: “I was happy to work on my 21st because I think why should I take a day off and sit at home by myself when I could be supporting those who need it? I think I can help the community and support the hospital.
“I’ve had great feedback from patients, who first say I must be crazy to volunteer in A&E, but then say the volunteers are doing an amazing job alongside the NHS staff."