It will be your passport to freedom but prepare to feel lousy for 24 hours after your receive your COVID-19 vaccine.

Clinical trial participants have warned short lived fever, headache, muscle pain and exhaustion are among the side effects.

And some doctors are worried these after effects might dissuade people from coming back for the second jab they will need to be properly protected.

US journalist John Yang, who volunteered to be Patient 232 in George Washington University's trial of Moderna's COVID vaccine, wrote about his experience of receiving the vaccine.

"I had been warned I might feel sick after getting the injection. I felt fine through bedtime, which disappointed me because it made me think I had gotten the placebo," he wrote in Pharmaceutical industry journal STAT.

"The next morning, though, I was paradoxically heartened to begin feeling feverish, fatigued, and achy - like I had a mild case of the seasonal flu. It felt good to feel bad.

"It wasn't enough to keep me from my daily routine, but it did persist. I felt a little better every day."

PBS NewsHour Award Winning Correspondent John Yang took part in a COVID vaccine trial. Picture: @johnyangtv/ Twitter
PBS NewsHour Award Winning Correspondent John Yang took part in a COVID vaccine trial. Picture: @johnyangtv/ Twitter

After his second shot he said it didn't take long for every muscle and joint in his body to ache and "my temperature to hit 99.9F (37.7C). I was in bed and asleep by about 7pm and didn't wake up until about 6am the next day".

However he reported just as the effects came on faster, they resolved faster.

Moderna reported that the majority of adverse events in its trial were mild or moderate in severity.

Around 2.7 per cent of people experienced injection site pain after the first dose and after the second dose 9.7 per cent suffered fatigue.

Muscle pain was common among 8.9 per cent of participants, 5.2 per cent had joint pain, 4.5 per cent had a headache, 4.1 per cent general pain and 2 per cent experienced redness at the injection site.

Jenny Hamilton, a former police officer from Atlanta, Georgia, took part in Pfizer's COVID-19 vaccine trial.

The 57-year-old told Business Insider after receiving the first two injections, she felt like she'd caught a virus and developed low-grade fevers, fatigue, and muscle aches.

Pfizer reported that of the 43,000 participants in its trial there were no serious safety concerns, 3.8 per cent of people suffered fatigue, 2 per cent suffered a headache.

Dr Paul Griffin, Medical Director, Nucleus Network. Picture: Patrick Rocca/ABC
Dr Paul Griffin, Medical Director, Nucleus Network. Picture: Patrick Rocca/ABC

In the AstraZeneca vaccine trial local injection site reactions and systemic reactions occurred in between two thirds and eight in ten participants.

Participants of the various trials were not told whether they received the actual vaccine or a placebo but assumed they did get the COVID jabs based on the symptoms they encountered.

Paul Griffin, the principal investigator for Nucleus Network which is trialling four COVID-19 vaccines, said "no vaccine will ever be produced that doesn't have some adverse effects".

"What's clear is that the benefit outweighs those risks and certainly if the benefit doesn't clearly outweigh the risks, we don't proceed with human trials," he said.

"The key thing is to make sure people are aware of what the adverse effects are likely to be and how to manage them."

He said people having the vaccinations should be told to prepare by having paracetamol or ibuprofen before the jab to reduce those effects.

"We know that a vaccine for this virus is a way to getting back to as close to normal as possible, and the trade-off of a bit of a sore arm for a few hours, or feeling of tired the afternoon of the vaccine would be a very acceptable price to pay for, for protecting yourself and everyone else," Dr Griffin said.

Originally published as Side effects of COVID-19 vaccine