Covid-19

Be prepared for Covid-19 vaccine side effects

Promising results from three different Covid-19 vaccines have raised hopes protection against the virus is in sight. However, this ‘warp speed’ effort may backfire if the public aren’t made aware of the likelihood of minor side-effects.

Vaccines under development by Oxford University, CanSino Biologics and Moderna have made headlines due to promising early trial results but all results point to a number of side effects.

None of these vaccines are approved for widespread use yet, with more trials needed, but they all have created an immune response to the virus. It’s not yet known if this response is enough to protect people against Covid-19 and if it does, how long the protection will last. 

Each of these vaccines had side effects in trials such as fatigue, fever, headache, muscle pain, or pain at the injection site. None of these were life-threatening, or bad enough to stop trials or prevent trials moving to the next development phase. They did occur at a higher rate than people may expect. 

The severity of the side effects may pale in comparison to the effects of getting Covid-19 and many people will be more than happy to trade off a fever and headache for a day for protection from a virus that has already killed over 600,000 people. 

With vaccine hesitancy an identified global health concern there's a risk not communicating likely side effects could see people lose trust in a vaccination programme.

University of Auckland vaccinologist associate professor Helen Petousis-Harris said potential side effects need to be talked about upfront. 

“People will lose trust and their confidence if you don’t.”

Side effects are normal “and not necessarily a bad thing either” she said.

“You don’t want them to be serious or severe but there’s a range of effects you get when your body is making an immune response.”

These can vary based on the type of vaccine technology used. A live vaccine often doesn’t give you a sore arm, but seven to 10 days later people who have been vaccinated are more likely to get a fever than people who haven’t.

A messenger RNA vaccine, such as Moderna’s is very “tasty” to the immune system.

“The immune system recognises danger signals so it will respond quite vigorously to RNA which is both an advantage and a disadvantage … it’s a matter of it being at an acceptable level and not causing much distress.”

Safe, but with side effects

All three vaccines have only been trialed so far in healthy people aged between 18 and 55.

The side effects ranged from mild to moderate or severe. 

Mild is defined as a reaction that does not interfere with daily activity, moderate symptoms are those that interfere with your day’s normal activity, severe reactions are those that stop you from doing normal activities. Life threatening reactions are those which require hospital care.

Moderna’s vaccine, which uses messenger RNA technology, is a new type of vaccine that has never been approved for use before. Results from a phase one trial of 45 people were published last week. Two injections were given 28 days apart and it was the second injection that caused the most issues. 

All the trial participants who received 100 or 250 microgram injections reported adverse systemic events such as fever, headache or fatigue and almost all experienced local symptoms such as pain, swelling or redness at the injection site after the second injection. Reactions listed ranged from mild to severe, with a dosage of 250 micrograms more likely to cause severe reactions. 

One study participant who received the higher dose suffered from a severe fever. “After sleeping for several hours at home, upon standing the participant was lightheaded and nauseous, vomited, and then fainted,” the study noted. He later said his girlfriend had caught him as he fainted and stopped his head from hitting the ground. He remained mildly fatigued for six days. 

The next trials of Moderna’s vaccine are not using the same high dose this man received. 

For Oxford University’s vaccine, around 70 percent of participants experienced fatigue, 68 percent had headaches, 60 percent muscle aches, 56 percent chills and 18 percent reported a fever. Symptoms ranged from mild to severe. Trials where participants were asked to take painkillers every six hours the day after the injection showed this reduced some side effects, but often didn’t help the moderate or severe side effects.

The CanSino Biologics Inc and China's military research unit vaccine was tested at two different dosages. For both groups, close to three quarters of participants reported adverse reactions. Most of them were mild to moderate. Around 9 percent of those who received a higher dose had a severe fever. This vaccine has been approved for military use in China for one year as a "specially needed drug".

All three vaccines are yet to complete the final phase of trials where thousands of participants from a cross section of society are given the vaccine. 

More than 100 other vaccines are in varying stages of development.

Petousis-Harris said even though a vaccine is still some time away, it’s a good time to start thinking about managing people’s expectations so side effects don't come as a surprise.

“That can be tailored as time goes on.”

She said it’s something New Zealand has done before for the Meningococcal B MeNZB vaccine where a side effect was a very sore arm after injection.

“That was talked about a lot in the media, and people were prepared for that. They actually over-talked it, and it wasn’t as bad, but it made people prepared.”

The fastest a vaccine has ever been created and approved for use is four years. 

Production logistics mean it’s unlikely billions of the first vaccine approved will be able to be produced immediately. It's possible several different vaccines may be used to combat the pandemic.

The Malaghan Institute is one of a number of players in New Zealand’s own vaccine strategy and with academics at the University of Otago and Victoria University of Wellington have been working on different vaccines. None of these is using new technology. 

“This is not a complicated virus. It’s a relatively simple virus in terms of making a vaccine. What’s difficult is the timeframe available for making it. People aren’t accepting it can be five years,” said Malaghan Institute’s director of research, Professor Graham Le Gros.

This urgency is pushing new technologies in vaccine-making to the fore such as Moderna’s messenger RNA approach. This offers a faster development and production time than traditional techniques.

Le Gros is uneasy that rushing some of the newer technologies could impact the public’s perception of the vaccination campaign.

”You’ve got bull-at-the-gate entrepreneurs trying to ram it [a vaccine] through, and you’ve got people who are deeply experienced with where things can go wrong saying ‘Hey, we don’t want to kill a vaccine programme because it was rushed before we knew all the things it can and cannot do’.”

The public’s tolerance for side effects has reduced in recent decades. Le Gros said he has a deep scar on his arm from a smallpox vaccine. Nowadays, that kind of reaction would be considered too severe for a vaccine to get approved.

While vaccines may have side effects, Le Gros doesn’t believe a vaccine which veers into unsafe territory will be approved.

“There’s a lot of knowledge, scrutiny and regulatory things in place to make sure nothing goes into a vaccine which could hurt people.”

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