If you or anyone close to you already got their COVID-19 vaccine, you would probably wonder when the immunity kicks in and how long it would last, or would you still be able to get infected and infect others? Therefore, it brings us to the question of what sort of precautions do you need to take after getting vaccinated?
Vismita Gupta-Smith in the World Health Organisation (WHO) ‘Science in 5’ section takes these questions to ask WHO’s Dr Kate O’ Brien.
After one has been vaccinated, when does the immunity kick in and how long does it last?
The vaccines that we have right now are all two-dose vaccines. After the first dose, we see a good immune response that kicks in within two weeks after the first dose, and it’s really the second dose that then boosts that immune response and we see immunity getting even stronger after that second dose.
We don’t know yet how long immunity lasts from the vaccines that we have at hand right now. We’re monitoring people who have received their vaccinations to find out whether or not their immune response is durable over time and the length of time for which they’re protected against the disease. So we’re really going to have to wait for time to pass to see just how long these vaccines last.
After one has been vaccinated, can one still catch COVID-19 and infect others?
That’s a great question. The clinical trials demonstrated that these vaccines protect people against the disease. What we don’t know yet from the clinical trials is whether or not the vaccines also protect people from just getting infected with the SARS-CoV-2 virus and whether or not it protects against transmitting to somebody else. So, this is really an important part of our understanding about what these vaccines do; if they only protect against the disease or do they also protect against getting infected and being able to transmit to somebody else, even if you’re not having any symptoms.
Why does one need to continue with the precautions even after vaccination, and how long are we expected to take these precautions?
We really need to continue with these precautions while we’re still learning about what vaccines can do. Right now, we’re in a situation where there’s still very broad transmission in many countries and the transmission is just out of control.
For how long we need to continue with these precautions is really going to depend on what communities and countries can do to crush this virus and its transmission. In this, the vaccines can do their best job at preventing disease.
But remember that we don’t actually have the evidence yet for using the vaccine in some age groups. We don’t have the evidence for the use of vaccines in young children, for instance.
For the time being, those age groups are going to continue to be at risk of both the disease and infection and being able to transmit to other people.
The second reason is that the vaccines are in short supply, so we don’t have enough vaccines yet out in the community to protect everybody. Those are the reasons why we have to continue with the precautions, especially the masking, the physical distancing, the hand washing and not gathering in big groups.
For how long do we need to continue those interventions? Only time will tell.
Once we get broad vaccination coverage in the community, and when we know more about what the vaccine can actually do to prevent infection, we can slowly start taking our foot off the pedal of these other interventions and make sure that the transmission, again, doesn’t start to escalate again.
Watch the full conversation on WHO’s YouTube channel here.
