Hyderabad, Nov. 13 -- Volunteers of the Pfizer vaccine trial have compared the jab's side effects to a 'severe hangover' and said it left them with headaches, fever, and muscle aches similar to the flu vaccine.

In a report byDaily Mail, volunteers shared how the vaccine showed the effect. While many said the first shot gave a fever, just like a regular flu shot, the effects of the second one were far more serious - including severe hangover, body aches, headaches among others.

Another volunteer quoted in the report said that the vaccine failed to develop an immune response. The 42-year-old engineer from Georgia had contracted COVID-19 after taking two shots.

More than 43,500 people in six countries have taken part in phase-three trials...