Sore arm, fatigue, muscle aches and fever are some of the side effects reported in those receiving COVID-19 vaccines, and according to experts, it is mostly a good thing.
Vaccines are supposed to elicit an immune response, they say. This is how you know they work.
“If you have a vaccine that does not respond to humans, the immune response from it is weaker,” said Earl Brown, a microbiologist at the University of Ottawa.
Brown says vaccines work by stimulating our immune cells to grow and communicate with each other, and gives directions on where to set up for a threatening attack by the virus. This leads to inflammation, with some of the cells moving to lymph nodes and causing swelling.
Read more:
What you need to know about COVID-19 side effects
The mRNA vaccines from Pfizer-BioNTech and Moderna give immune cell instructions to make the COVID protein and produce antibodies. Viral vector vaccinations such as Oxford-AstraZeneca and Johnson & Johnson, meanwhile, are forcing an immune response from the harmless version of the virus injected with the jabs.
‘The vaccines make your immune cells recruit more of their mates and say’ we respond in a new way. We need everyone here, ‘Brown said. ‘So the inflammation is good. It strengthens the immune system. ”
The World Health Organization says side effects of COVID vaccines were mostly ‘mild to moderate and short-lived’ and include: fever, fatigue, headache, muscle aches, chills, diarrhea and injection site pain.
But how often does this happen?
Dr. Lynora Saxinger, an infectious disease expert at the University of Alberta, says cases of adverse effects are increasing because so many people are now being vaccinated. The percentage of those who develop these mild to moderate side effects is still quite low compared to the number of people who are vaccinated.
She notes that although worse effects are possible – a small number of severe allergic reactions are experienced – these events are rare.
[ Sign up for our Health IQ newsletter for the latest coronavirus updates ]
Fever was common after the first dose of Pfizer and ‘very common’ – defined as present in 10 percent of participants or more – after the second dose. It was uncommon after the first dose of Moderna, but very common after the second dose.
Brown says the effects are generally clearer after second doses because the body has built up a stronger immune response from the initial sting.
Read more:
No scientific statement linking AstraZeneca vaccine to blood clots, says Sharma
Saxinger says fever is a ‘strong reaction’ to a vaccine, but it should not last longer than a few days. She also says that the use of anti-inflammatory drugs before a vaccine is not recommended as you want to ban the immune response.
“It seems that mRNA vaccines are particularly talented at mimicking infections,” she added. “That very purposeful and strong immune response is what we ultimately want.”
Data from Health Canada shows that 0.085 percent of the doses administered in the country from mid-December to March 5 resulted in an adverse reaction, with 0.009 percent considered serious. Pain, redness and swelling at the vaccination site were the most common effects.
Most of these doses would have been mRNA vaccines, which usually elicit stronger reactions than the viral vector disorders.
Saxinger says this may be related to the initial efficacy of the vaccines. While Pfizer and Moderna immediately offer higher efficiencies, AstraZeneca and Johnson & Johnson build over time.
“It’s more of a slow and steady profile versus the hot-off-the-press, quick response of the mRNA,” she said. “So there is a parallel with the strength of the initial immune response.”
But why do some people experience side effects while others do not?
Brown says age is perhaps the biggest determining factor, and noting older people, who tend to have less robust immune systems, report fewer reactions. Canada’s vaccine supply has so far mostly been administered to older populations.
The absence of side effects does not mean the vaccine does not work, Brown added. Some people simply do not show outward reactions.
News outside Europe last week expressed concern about AstraZeneca’s product after some adverse events, including blood clots, were reported following the vaccination. This has prompted nearly a dozen countries to suspend their use of the product while experts investigate a possible link.
Canadian health authorities have said they are monitoring Europeans’ investigations, but add that there is no evidence that the blood clots were caused by the vaccine.
AstraZeneca on Sunday issued a statement saying a survey of 17 million patients who received the shot in Europe and the UK showed no increased risk of blood clots.
Read more:
There have been no serious side effects from COVID-19 vaccines so far, says Health Canada
Ann Taylor, the company’s chief medical officer, said there was no increased risk of pulmonary embolism, deep vein thrombosis or thrombocytopenia in any age group, gender, vaccine group or country.
The company said there were reports on March 8 of 15 patients experiencing deep vein thrombosis and 22 pulmonary embolisms, which is much lower than would naturally occur in a population of more than 17 million people.
Saxinger says blood clots are fairly common, so investigators will look at the total number of people who received the AstraZeneca vaccine compared to those who reported the condition.
“There are so many people who receive vaccinations daily that any health event that happens to someone during the time they are shot is related or not,” Saxinger said.
Brown says news of possible side effects should not stop people from being vaccinated.
“Consider it short-term, manageable discomfort without harm, compared to a real illness that can be life-changing or life-threatening.”
View link »
© 2021 The Canadian Press