Volunteers discuss side-effects after receiving Moderna and Pfizer Covid-19 vaccines

Moderna and Pfizer announced their potential vaccines had been tested to 94.5 per cent and 95 per cent efficacy respectively

Volunteers who received two of the potential coronavirus vaccines in the US have spoken out about the side-effects they experienced following their jabs.

This month, Moderna and Pfizer announced their vaccine candidates had been tested to 94.5 per cent and 95 per cent efficacy respectively.

Jennifer Haller, who was injected on 16 March with Moderna’s experimental vaccine in Seattle, told WVPI-TV she only experienced mild side-effects as a result.

"I had two doses of the vaccine four weeks apart,” she told the broadcaster.

“Each time my arm was pretty sore the next day but besides that I personally didn't experience any other side effects."

Ms Haller was the first person to receive a shot of Moderna’s candidate at the Kaiser Permanente Washington Health Research Institute as part of the first human trial of a vaccine to prevent the virus.

California resident, Daniel Horowitz, who participated in Pfizer's Covid-19 vaccine trial in September, described flu-jab-like symptoms to WVPI.

Pfizer’s trial is double-blind, meaning both doctors and patients don’t know who is receiving the vaccine or placebo therefore Mr Horowitz is unaware if he received the vaccine. 

However, he told the broadcaster he also felt mild side effects after the jab.

"I got a little ache in my muscles, like… I just don't feel right and it went away after that day," he said.

Pfizer submitted its vaccine to the US Food and Drug Administration (FDA) for emergency use on 20 November and Moderna will submit its vaccine later this month.

Common side-effects of vaccines include pain, swelling, or redness at the injection site, mild fever, chills, fatigue, headache and muscle and joint aches.

The US Department of Health and Human Services says the most common side-effects are a sign that your body is starting to build immunity against a disease.

"25 per cent to 50 per cent of people might feel some mild side effects after their first dose,”  Dr Peter Chin Hong, an infectious disease specialist at the University of California, San Francisco, told WVPI-TV.

“But, after the second one they may be more people who might feel some of these side effects and they might go away within a day or so.”

A total of 30,000 people have been enrolled in Moderna’s latest trial of the vaccine. More than 43,500 volunteers from six countries were involved in Pfizer’s trial.

Volunteers who received the Pfizer coronavirus vaccine reportedly said earlier this month that the jab left them with side effects that felt similar to a “severe hangover".

Operation Warp Speed, an initiative created by the US government to facilitate vaccine development, have said they are planning to ship vaccines to the immunisation sites within 24 hours of their approval from the FDA.

More than 12.8 million people have been infected with the novel coronavirus in the US since the outbreak gripped the country in March, leading to the deaths of nearly 262,000 people.