Coronavirus: What happens after being vaccinated?

Most people feel relieved after the vaccination, but when can you start to feel safe, and does the vaccination also protect others?

When does the vaccination take effect?

Regardless of which vaccine you get, you won’t reach full protection until two weeks after your second or final dose. That’s roughly how long it takes your immune system to mount an antibody response to the vaccine. All vaccines work this way. Think of it in terms of when you have a cold—it takes your body a good amount of time to rid itself of what’s making you sick. A vaccine is essentially tricking your immune system in to triggering a similar response. After the jab, your body has some work to do.

Coronavirus: What happens after being vaccinated?

With most vaccines two injections are necessary for the vaccines currently approved to fully develop their protective effect. The second dose of the AstraZeneca vaccine should be given four to twelve weeks after the first, while the other two vaccines from BioNTech / Pfizer and Moderna should be given four weeks after the first vaccination.

As early as two weeks after the first dose, a certain protective effect has built up with all three vaccines. BioNTech / Pfizer and Moderna are fully vaccinated about one week after the second dose; AstraZeneca is two weeks. None of the three vaccinations offer complete protection.

Will the vaccination protect me 100%?

A person immunised with a vaccine that has, say, 80% efficacy is very likely to be protected from getting the disease with symptoms, especially severe ones. They are also very likely to be protected from asymptomatic disease – but this, depending on the vaccine, may be less certain. Even with 95% efficacy, there is no absolute guarantee of protection for any particular individual.

In the real world, a vaccine’s effectiveness can be influenced by multiple, unpredictable factors including, for example: the rate of spread of a virus; how many, or few, people adhere to the optimum dosing schedule and timetable; how individuals’ immune systems respond; whether the vaccine was stored at the correct temperature; whether people know, or don’t know, if they’ve been exposed before.

Generally, a vaccine’s real-world effectiveness tends to be slightly lower than its stated efficacy.

Can I still infect other people despite being vaccinated?

Studies primarily looked at whether the vaccines could prevent the Covid-19 outbreak. However, it is still unclear whether the vaccination will also prevent you from becoming infected without developing symptoms and then potentially infecting others.

Evidence so far suggests that COVID-19 vaccines developed by Pfizer-BioNtech, Moderna and AstraZeneca will help stop people developing the disease. Only AstraZeneca’s data, so far, shows signs that its shot may also help prevent transmission of the virus.

Do I still have to wear a mask?

Yes. The prevailing rules continue to apply to people who have already been vaccinated and it will stay likely this way until clear to what extent people who have been vaccinated can infect others. However, for reasons of fairness, everyone could still be required to wear a mask until everyone who wants to be vaccinated has had the opportunity to do so.

The vaccine is no good until people are vaccinated, and even then, it will not result in a situation where all other protective measures can be immediately abandoned.

What do I do if I notice Covid-19 symptoms?

To be on the safe side, you should do a rapid coronavirus test because people who have been vaccinated can also become infected – and then pass the virus on.

What do I do if think I am experiencing side effects?

Reactions to the vaccination are normal. Fever, fatigue or pain at the injection site indicate that your immune system is responding to the vaccination. However, other or more serious complaints could arise soon after the vaccination. It could be sheer coincidence – or there is actually a connection. If you are unsure, talk to your doctor or provider about it. In most cases, discomfort from pain or fever is a normal sign that your body is building protection.


  • Side effects can affect your ability to do daily activities, but they should go away in a few days.
  • If you get a COVID-19 vaccine and you think you might be having a severe allergic reaction after leaving the vaccination site, seek immediate medical care by calling the emergency helpline numbers within your location.
  • It takes time for your body to build protection after any vaccination. People are considered fully vaccinated two weeks after their second jab of the COVID-19 vaccine. You should keep using all the tools available to protect yourself and others until you are fully vaccinated.
  • We are still learning how vaccines will affect the spread of COVID-19. After you’ve been fully vaccinated against COVID-19, you should keep taking precautions in public places like wearing a mask, staying 6 feet apart from others, avoiding crowds and poorly ventilated spaces, and washing your hands often.

Only time will tell

At this stage there are still more questions than answers and nobody knows for sure how effect the vaccines will be at protecting people and stopping the spread of the virus. All eyes now will be on Israel, the UAE and the UK which are leading the race to get the bulk of their populations vaccinated. Soon after this is achieved this what happens next in these countries will provide a lot of the answers we are all waiting for. For now though whether vaccinated or not, and for the sake of others, we should all keep wearing masks and behaving responsibly until more conclusive, and hopefully positive, data emerges.