As more and more people are getting vaccinated against the Coronavirus, there has been a palpable sense of relief amongst the masses. 

However, there must be many questions still lingering in your mind about what getting vaccinated means at this stage of the pandemic. 

You may wonder if you can catch a COVID-19 infection after one or both doses of vaccination. You may also worry if you can spread the infection to others, especially if other family members are not yet fully vaccinated. 

Read on to find out more.

Breakthrough Infections

A person is considered fully vaccinated at about 2-3 weeks after receiving the second dose of a double-dose COVID-19 vaccine. Most of the vaccines authorized for COVID-19 have high efficacy, ranging from about 79% to 95%. 

Since none of these vaccines have 100% efficacy (the ability of the vaccine to reduce disease under optimal conditions) or 100% effectiveness (the ability of the vaccine to reduce disease incidence under real world circumstances), a small percentage of fully vaccinated individuals may develop symptomatic or asymptomatic infections with the novel Coronavirus. 

A vaccine breakthrough infection is defined as the detection of COVID-19 infection in a person after 2-3 weeks of receiving the final dose of a COVID-19 vaccine. 

The COVID-19 vaccines protect against serious illness and usually, breakthrough infections are rare and mild in nature. 

Can You Still Transmit The Coronavirus After Being Vaccinated?

Scientists believe that COVID-19 vaccination reduces the transmission of Coronavirus from the vaccinated individual. However, it is difficult to confirm if vaccinated people are not spreading the virus.

Especially with COVID-19, people with asymptomatic and symptomatic infections can spread the disease. Thus, a person, who does not exhibit symptoms and does not undergo testing, may spread the disease to others. It can be a similar situation for a vaccinated person as well. 

As per the US Centres for Disease Control and Prevention (CDC), 

“We are still learning how well vaccines prevent you from spreading the virus that causes COVID-19 to others, even if you do not have symptoms. Early data show that vaccines help keep people with no symptoms from spreading COVID-19.”

Some studies have found that people who tested COVID-19 positive after getting the first dose of vaccination had lower levels of the Coronavirus in their bodies as compared to unvaccinated people who tested COVID-19 positive.  

Researchers suggest that the decreased viral load may mean that vaccinated people who do contract COVID-19 will have a low potential to transmit the virus. However, more studies are needed to confirm these findings. 

Also, contact tracing (identifying individuals who may have come in contact with an infected person) would be needed to track the transmission of Coronavirus by vaccinated and unvaccinated individuals in a larger population.

Lastly, scientists are also concerned about Coronavirus variants, and whether they may reduce the effectiveness of COVID-19 vaccines, which could also affect the transmission of infection after vaccination.

Thus, it cannot be confirmed that a fully vaccinated person does not transmit the Coronavirus to others. 

If you are fully vaccinated, do not assume complete immunity against COVID-19 or the absence of the risk of infecting others. For the safety of people who cannot or have not yet been vaccinated, continue to follow masking (preferably double masking), social distancing, respiratory hygiene, and hand hygiene practices. 


1. 2021. Mounting evidence suggests COVID vaccines do reduce transmission. How does this work?. [online] Available at: <> [Accessed 8 June 2021].

2. Centers for Disease Control and Prevention. 2021. Coronavirus Disease 2019 (COVID-19). [online] Available at: <> [Accessed 8 June 2021].

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