How the vaccines work

All vaccines contain ingredients that help your immune system make antibodies (proteins that fight off infection and disease).

If you get a vaccination and then come into contact with the bacteria or virus (germ) that causes the disease, your immune system will recognise it and be able to protect you by producing the right antibodies.

Coronavirus (COVID-19) vaccination offers good protection within 3 to 4 weeks of the first dose.

Having all the recommended doses of the vaccine is important for longer-term protection against coronavirus.

How the coronavirus vaccines work

The coronavirus has a spike protein on its surface that helps it enter human cells. The coronavirus vaccines help your body make antibodies that recognise this spike protein and can then fight off the virus.

The vaccines contain ingredients that give your body instructions to produce the spike protein, using the virus’ genetic code.

Then, your body makes antibodies that can recognise the spike protein on the coronavirus if it enters your body and help fight it off. This means that if you choose to take a vaccine, you are less likely to get severely sick if you encounter the coronavirus.

Your body’s response to a vaccine is similar to when it encounters a natural infection, but it is safer to gain protection from a disease by taking a vaccine because the vaccines do not contain a live virus and cannot cause disease.

The vaccines cannot change your DNA.

More about the coronavirus (COVID-19) vaccines

Herd immunity

Choosing to get a vaccine is good for you and your community. A vaccine will protect you as an individual against a disease.

As more people in a community take a vaccine, fewer people can become sick and pass on the disease to others. This helps protect people in the community who cannot take a vaccine, like young children or people who are vulnerable. This is called herd immunity or herd protection.

Scientists don’t know yet how many people will need to have a coronavirus vaccine in order for herd immunity to protect communities, so it’s important to continue to follow the latest government advice.

Vaccine development

While it usually takes years to develop a new vaccine, the coronavirus vaccines were able to be developed quickly because scientists could build on work they had already done on vaccines for other diseases.

Creating a vaccine for coronavirus was a priority for scientists, industry and other organisations. They worked together and a lot of resources were made available across the globe to complete phases of vaccine development at the same time, rather than one after the other, so a safe vaccine could be developed as soon as possible.

Vaccine safety

All medicines, including vaccines, are tested for safety and effectiveness before they’re allowed to be used. Their safety continues to be checked while in use.

NHS Scotland will only use a vaccine if it meets the required standards of safety and effectiveness.

The Medicines & Healthcare products Regulatory Agency (MHRA) has approved coronavirus vaccines for use in the UK.

Tens of millions of people have been vaccinated in the UK vaccination programme and many thousands of lives have already been saved.

Vaccine side effects

As with all vaccines, you may have some side effects after having the coronavirus vaccine. This does not mean the vaccine is not safe.

Common side effects can affect more than 1 in 10 people who take the vaccine. These reactions are usually mild and last only a day or two. They are part of the body’s normal immune response to a vaccine.

Not everyone will experience side effects after the vaccine. If you don’t have any side effects, the vaccine is still working.

More about side effects of the vaccines

Monitoring vaccine safety

Side effects are continuously monitored by the Medicines & Healthcare products Regulatory Agency (MHRA) through the Coronavirus Yellow Card scheme. You can report any side effects that you may experience here.

The Yellow Card scheme is one of four activities that the MHRA is carrying out to monitor the safety of the new coronavirus vaccines.

More about vaccine safety surveillance

Other variants

Like many viruses, coronavirus changes, or mutates, over time. This results in new forms, or variants, of the virus.

The current vaccines are likely to offer some protection against new variants of coronavirus. Scientists and public health officials in Scotland are tracking changes in coronavirus to make sure the vaccines continue to be as effective as possible.

Last updated:
05 May 2022