COVID-19 Vaccines: Are they safe? For everyone? What do they mean for the pandemic?

November 27, 2020

Three vaccines have now announced promising trial results, bringing us all hope that the pandemic will be over soon, and we will all be able to resume our lives. 

But how do they work? Are they safe? And when will we get back to normal?

To find out, Professor Tim Spector, ZOE COVID Symptom Study lead, spoke to leading immunologist, Professor Peter Openshaw from Imperial College London, to answer some of your top questions about COVID vaccines.

How do the vaccines work?

Four vaccines have announced successful large-scale clinical trial results so far:

  1. The Pfizer-BioNTech vaccine uses mRNA, a messenger molecule that tells your cells to produce the coronavirus spike protein, which triggers an immune response. Showed 94% efficacy in clinical trials. 
  2. The Moderna vaccine is also an mRNA vaccine and showed 95% efficacy in clinical trials.
  3. The Oxford-AstraZeneca vaccine uses a weakened harmless common cold virus which can’t replicate in your body to deliver genetic material to your cells, telling them to produce the COVID spike protein. It showed 70% efficacy in clinical trials. 
  4. The Sputnik V vaccine - also uses a weakened common cold virus to deliver genetic material. Showed 95% efficacy in clinical trials. 

How can we be sure that COVID-19 vaccines are safe?

“Although they’ve been developed with incredible speed, safety has not been compromised,” says Prof Openshaw.  

He likens normal vaccine development processes, which often takes years, to trying to drive a milk float across a city at rush hour. You inevitably sit in traffic, wait at lights, and maybe even run out of battery, so you have to stop to recharge halfway, which all slows you down. 

“In this case, there’s been so much money poured into the process that it’s like the milk float has a police escort and all the traffic lights are on green,” he says. “But it doesn’t mean to say that the route that has been taken is any different. All the normal safety checks are in place.”

All vaccines undergo stringent laboratory testing before going into clinical trials in human volunteers, and researchers continue to monitor trial participants to check for any side effects and long term impacts. 

How will COVID-19 vaccines affect different people?

Ahead of our webinar, many people raised concerns about how the vaccine might affect them if they have already had COVID-19, are suffering from long COVID, or have a pre-existing health condition.

“We have no reason to think that people who have antibodies because of natural COVID-19 infection would behave any differently from people who haven’t, except that they would have a higher baseline of protection,” says Prof Openshaw. 

Right now, we can't be sure of the effects of the vaccine on people with long COVID, partly because we don’t fully understand what is going on with the immune system in people who experience long term symptoms. However, based on the evidence we have so far, Prof Openshaw doesn’t believe the vaccine would be harmful to people living with long COVID.

If you are in a high COVID-19 risk group due to an underlying health condition, you may be worried about how the vaccine will affect you as an individual. 

But many of the vaccine studies were designed to include a wide variety of people with a range of risk levels, such as the elderly, pregnant women, and ethnic minorities so that they could observe if the vaccines are safe and effective in all these different groups. 

We’ll know more about the effects of the vaccines on different groups when the full results are published, but right now, there’s no cause for concern. 

When the time comes for national roll-out of vaccination, some people may be unable to receive a COVID-19 vaccine due to underlying health issues or allergies. In this case, your doctor will be able to advise on whether the vaccine is right for you.

How will COVID-19 vaccines change the course of the pandemic?

The UK government has taken out contracts to buy 340 million doses of COVID-19 vaccines, including the Pfizer, Moderna and Oxford vaccines, which is enough to cover the entire population. 

The Joint Committee on Vaccination and Immunisation (JCVI) has published a list of eleven different vaccination groups, starting with the highest priority groups who are most at risk of becoming severely ill or dying from COVID-19 and working down from there.

“The first few groups are relatively small numerically but are currently contributing a lot to the number of cases, including care home workers and residents,” says Prof Openshaw. 

Targeting these groups first will reduce the number of deaths significantly and protect the most vulnerable, but it means that most people won’t be offered a vaccination until at least Spring 2021. 

A national vaccine roll-out on this scale will take time. We need to reach around 70% vaccination levels across the UK population to allow us to return to everyday life.

How you can help COVID-19 vaccine research 

At the ZOE COVID Symptom Study, we’re doing our bit to support vaccine development. 

Our vaccine registry matches volunteers with COVID vaccine trials that need participants. You can sign up if you’d like to be contacted about taking part in COVID-19 vaccine trials.

We’ll add a section to the app where you can report whether you’ve had a COVID-19 vaccine, to help us understand more about the health effects of vaccination.

Your daily health reports help us understand more about the virus and are informing vital COVID-19 vaccine research. Download the app now and take a minute to log your health every day to play your part in helping to stop the pandemic.

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