COVID-19 Vaccines – FAQs

Our Medical Director MATT EDWARDS answers your questions about the Coronavirus vaccine. Last updated 27 May 2021.

How does a vaccine work? It trains and prepares the body’s natural defences (aka the immune system) to recognise and then fight off the virus or bacteria that it targets. If the body is later exposed to these disease-causing infections, it is quickly ready to destroy them, thus preventing illness. Vaccines save millions of lives each year. And when someone gets vaccinated, they aren’t just protecting themselves, but also those around them. 

How many different vaccines are there? There are several vaccines in use and at least 13 different vaccines have been administered. 

Do the vaccines work in the same way or are there different types? Out of the 60+ vaccines that have been developed there are several different types: 

  • Inactivated or weakened virus vaccines, using a virus that doesn’t cause disease, but still generates an immune response.
  • Protein-based vaccines, using harmless fragments of proteins that mimic the COVID-19 virus to safely generate an immune response.
  • Viral vector vaccines, using a genetically engineered virus that can’t cause disease, but produces virus proteins to safely generate an immune response.
  • RNA and DNA vaccines, using this cutting-edge approach with genetically engineered RNA or DNA to generate a protein that safely generates an immune response.

How does a vaccine get approved? Vaccines must be proven to be safe and effective in large clinical trials. Once they are demonstrated to be safe and efficacious, they must be approved by national regulators, manufactured to exacting standards, stored and safely distributed. 

Are the vaccines safe? Vaccines go through rigorous testing for safety and effectiveness before they are approved for public use. This process previously has taken years. With the global pandemic, researchers around the globe have safely accelerated the process in a number of ways, such as by carrying out stages of development simultaneously, by looking to new vaccine technologies, as well as unprecedented financial investments and scientific collaborations. The Covid-19 vaccine has had to meet all the expected robust clinical milestones with no safety shortcuts. No regulatory steps were omitted in the reported vaccine development.

So far, almost 1.5 biillion doses of a COVID-19 vaccine have been administered globally and reports of serious side effects, such as allergic reactions, have been very rare. No long-term complications have been reported thus far. There are NOT microchips or magnets in the vaccines.

How effective are the COVID-19 vaccines? Most of the currently used COVID-19 vaccines are a 2 dose vaccine. The 1st dose generally gives good initial protection from the coronavirus. Both doses of the vaccine are needed to give full vaccination and longer lasting protection. The 2nd dose is generally given 3 to 12 weeks after having the 1st dose. There are some studies looking at the optimum time for the 2nd dose and whether this can be extended further.

There is a chance that someone vaccinated might still get (to a less severe extent) or spread coronavirus so it is important to continue to adhere to transmission reduction measures – hand, respiratory hygiene, general hygiene, ventilation and distancing measures.

What are the side effects of the COVID-19 vaccine? This may vary slightly vaccine to vaccine but most side effects of the COVID-19 vaccine are mild and only last a few days. Before having the vaccine make sure you read the information given to you about the specific one you are having. The most common potential side effects include:

  • a sore arm 
  • feeling tired
  • feeling achey
  • nausea – feeling sick

Is there a preference of one vaccine over another? Currently there is no major known benefit of one vaccine over another. The evidence at this stage is not available to direct us to one being ‘better’ than another. There are some differences in production, handling and storage which can affect practical preference and also the availability in a specific country. The encouragement at this stage is to have a vaccination rather than be concerned about which one.

There have been some concerns about the AZ/Oxford vaccine, what is the latest about this? Safety is of paramount importance with the vaccines. The benefits of this vaccine outweigh any risks in adults of all age groups. However, extremely rare cases of blood clots with low levels of platelets have been observed following vaccination with the AstraZeneca COVID-19 Vaccine. The majority of these cases occurred within the first 14 days following vaccination but some have also been reported after this period. Some cases were life-threatening or had a fatal outcome. It is important to remember the benefits of vaccination to give protection against COVID-19 still outweigh any potential risks.

How is delivery of the vaccine being rolled out? In countries where vaccines are being used, they are currently being given to frontline health care workers, to the most clinically at risk and the most vulnerable. 

What about the new strains? There have been several new strains of the coronavirus that have emerged which have caused concerns about increased transmission and potentially reduced effectiveness of vaccines that have already been developed. It remains to be seen, but there are some ‘promising’ results from some early studies into how well existing vaccines work against the new strains. A number of companies are already developing booster vaccinations to increase protection against the new strains.

Is the vaccine available privately? No, and it is unlikely any time soon. 

Will COVID-19 vaccines provide long-term protection? It’s too early to know if the COVID-19 vaccines will provide long-term protection. Most people who recover from COVID-19 appear to develop an immune response that provides at least some period of protection against reinfection – although we’re still learning how strong this protection is, and how long it lasts. The same goes for the vaccination. There is a suggestion that it may need to be a regular yearly vaccination boosted to cover new strains.

Can pregnant women have the vaccine? Because of how the vaccines work experts think they are unlikely to be a specific risk pregnancy. However, there is currently limited data on the safety of COVID-19 vaccines in pregnancy as these vaccines have not been widely studied in pregnant women. With the systems in place to continue to monitor vaccine safety so far, they have not identified any specific safety concerns for pregnant women. This should be discussed after an individual risk evaluation with the supporting healthcare clinician. 

What about people with allergies? You should not have the COVID-19 vaccine if you have ever had a serious allergic reaction (including anaphylaxis) to a previous dose of the same vaccine or any of the ingredients in the vaccine. Serious allergic reactions however are rare. 

Why is the vaccine only currently available only for adults? COVID-19 vaccine trials have so far focused on adults, and safety data is currently restricted to adults in vaccine trials, with limited data in children. Also, the low rates of severe disease and death associated with COVID-19 infection in children and young people would suggest that during the early vaccine deployment they do not need to be prioritised for vaccination.  

Can I stop taking precautions after being vaccinated? The vaccination protects an individual from getting seriously ill and dying from COVID-19. It takes fourteen days after getting a vaccination to get significant levels of protection and then it further increases gradually from then. After a single dose vaccine, immunity generally occurs about two weeks after vaccination. After a two-dose vaccine, both doses are needed to achieve the highest level of immunity possible. While the vaccine will protect us from serious illness and death, we still don’t know how much they keep us from being infected and passing the virus on to others. To help keep everyone safe we need to continue with the general prevention measures. 


What if I have had COVID-19, do I still need the vaccination? Yes, the vaccination is still recommended due to the severe health risks associated with COVID-19 and the fact that re-infection with COVID-19 is possible. It’s also not known yet how long the antibodies made by your body in response to COVID-19 last, so a vaccine could offer more protection or boost any antibodies your body has already made.

Can a COVID-19 vaccine make me sick with COVID-19? No. None of the authorised and recommended COVID-19 vaccines contain the live virus that causes COVID-19. This means that the vaccine cannot make you sick with COVID-19.

After getting a COVID-19 vaccine, will I test positive for COVID-19 on a test? No. None of the current vaccines can cause you to test positive on the viral tests that  are used to see if you have a current infection.​

Can a COVID-19 vaccine alter my DNA? No. COVID-19 vaccines do not change or effect your DNA in any way.

Is it safe to get a COVID-19 vaccine if I want to get pregnant one day? Yes. If you want to get pregnant at some point, you can receive a COVID-19 vaccine when one is available to you. There is no evidence to suggest the vaccine affects fertility.

Where can I find reliable information? Various websites and sources can be used for reliable and up to date information, such as:;;;

If you would like to know about our COVID-19 testing service then click here.

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