Vaccinated but Infected: Breakthrough Cases After BNT Shot

Q: Vaccinated but Infected: Breakthrough Cases After BNT Shot

Hello： Although your boyfriend contracted the virus after receiving the third dose of the vaccine, the vaccine is still effective. <br>Both vaccination and COVID-19 infection stimulate the production of antibodies in the body, and their effects do not cancel each other out. <br>I

Just got vaccinated and then contracted the virus?

My boyfriend just received his third dose of the BNT vaccine on May 26 (the first two doses were also BNT).
He developed a fever on the night of vaccination, which persisted into the next day.
Initially, we thought it was just a normal side effect of the vaccine and didn't pay much attention.
However, on the evening of May 28, he experienced throat discomfort and decided to take a rapid test, which surprisingly came back positive.
We are unsure when he might have contracted the virus.
Could you please advise if the third dose of the BNT vaccine is still effective under these circumstances? Thank you.

A Miao, 30~39 year old female. Ask Date: 2022/06/03

Dr. Lin Zhebin reply Family Medicine

Hello: Although your boyfriend contracted the virus after receiving the third dose of the vaccine, the vaccine is still effective.
Both vaccination and COVID-19 infection stimulate the production of antibodies in the body, and their effects do not cancel each other out.
In the future, both will help reduce the risk of infection and decrease the severity of the disease, so there is no need to worry too much.

Reply Date: 2022/06/03

More Info

Vaccination against COVID-19, including the BNT (BioNTech/Pfizer) vaccine, is a crucial public health measure aimed at reducing the severity of illness, hospitalization, and death caused by the virus. However, breakthrough infections—cases where vaccinated individuals still contract the virus—can occur. Understanding these cases is essential for both public health and individual health management.

In your situation, your boyfriend received his third dose of the BNT vaccine on May 26 and subsequently tested positive for COVID-19 on May 28. It’s important to note that while vaccines significantly reduce the risk of severe illness and hospitalization, they do not guarantee complete immunity against infection. Breakthrough infections can happen, especially in the context of emerging variants of the virus that may partially evade the immune response generated by the vaccine.

The timing of your boyfriend's infection is also noteworthy. Vaccines typically take about two weeks to build up a robust immune response. If he was exposed to the virus shortly before or after vaccination, it is possible that he contracted the virus before the vaccine had fully taken effect. This is a common scenario, as the vaccine does not provide immediate protection.

Moreover, the symptoms he experienced, such as fever and throat discomfort, are consistent with both vaccine side effects and COVID-19 symptoms. It can sometimes be challenging to differentiate between the two, especially in the early days following vaccination. The fever he experienced on the night of vaccination is a common side effect, indicating that the immune system is responding to the vaccine. However, if symptoms persist or worsen, it is crucial to seek medical advice.

Regarding the effectiveness of the vaccine after a breakthrough infection, it is essential to understand that the vaccine still provides significant benefits. Even if someone contracts COVID-19 after vaccination, the vaccine can help mitigate the severity of the disease. Studies have shown that vaccinated individuals who do contract COVID-19 tend to experience milder symptoms compared to unvaccinated individuals. This is particularly important for reducing the risk of severe outcomes.

In terms of future vaccinations, if your boyfriend has tested positive for COVID-19, he should wait at least 90 days before receiving another dose of the vaccine. This is to allow his body to recover fully and to avoid any potential interactions with the immune response triggered by the infection.

In summary, while your boyfriend's positive test after vaccination may seem concerning, it does not mean that the vaccine was ineffective. Vaccination remains a critical tool in controlling the pandemic, and breakthrough infections, while unfortunate, are a known aspect of the vaccination landscape. It is essential to continue monitoring symptoms and to follow public health guidelines regarding isolation and treatment. If symptoms worsen or new symptoms arise, seeking medical attention is advisable.

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