People Vaccinated Against COVID-19 May Still Get Sick
People who have received a COVID-19 vaccine can still become infected and develop COVID-19. Vaccination is not expected to prevent every infection, and protection can change over time as immunity wanes and new variants circulate. Current CDC monitoring specifically evaluates protection against infection as well as hospitalization and death. CDC+1
1. Vaccination Does Not Mean You Can Never Get COVID-19
COVID-19 vaccines are not a guarantee that a vaccinated person will never become infected.
A vaccinated person can encounter SARS-CoV-2 and still develop an infection. These infections are commonly called breakthrough infections.
This is not unique to COVID-19 vaccines. No vaccine provides 100% protection against infection.
The important question is not simply whether infection can occur, but how well vaccination protects against the most serious consequences of infection. CDC
2. Protection Against Severe Illness Is Especially Important
COVID-19 vaccination has been shown to provide protection against severe outcomes, including hospitalization and critical illness.
CDC data for the 2023–2024 vaccines found reduced risks of COVID-19 hospitalization and critical illness, although protection declined over time. CDC
This is why getting COVID-19 after vaccination does not necessarily mean that vaccination provided no benefit.
A person may still become sick but have a substantially lower chance of progressing to severe disease.
3. Immunity Can Decrease Over Time
Protection isn’t necessarily constant forever.
CDC explains that vaccine effectiveness can vary according to:
- Time since the most recent dose
- Age
- Underlying medical conditions
- Previous infection
- The circulating variant
- Vaccine product and dose history
Protection against infection can decline more noticeably over time, while protection against severe disease can persist longer. CDC+1
4. New Variants Can Change Protection
SARS-CoV-2 continues to evolve.
When a new variant has characteristics that allow it to partially evade existing immunity, vaccinated people can still become infected.
This is one reason vaccine effectiveness is continuously monitored and vaccine recommendations can be updated.
It doesn’t mean that previous vaccination suddenly becomes useless.
5. Symptoms Can Still Occur
A vaccinated person who develops COVID-19 can experience symptoms such as:
- Sore throat
- Cough
- Runny or blocked nose
- Headache
- Fatigue
- Fever or chills
- Muscle aches
- Nausea
- Diarrhea
Symptoms vary from person to person.
Some infections may also produce few or no noticeable symptoms.
6. Older Adults Remain an Important High-Risk Group
Age is an important factor when considering COVID-19 severity.
Older adults and people with certain underlying conditions can remain vulnerable to severe disease even when vaccinated.
For these individuals, staying informed about current vaccination recommendations and seeking medical advice early when they become ill can be particularly important. CDC specifically monitors vaccine effectiveness in populations at higher risk of severe COVID-19. CDC
7. Previous Infection Doesn’t Make Vaccination Irrelevant
Someone who has already had COVID-19 can develop another infection.
Previous infection provides some immune protection, but its strength and duration vary, particularly as the virus evolves.
CDC notes that vaccination can provide additional protection, including against hospitalization following subsequent infection. CDC+1
8. Don’t Blame Every Illness on the Vaccine
It’s important to distinguish COVID-19 infection from vaccine reactions.
Short-term reactions following vaccination can include:
- Arm soreness
- Fatigue
- Headache
- Muscle aches
- Chills
- Fever
These generally occur soon after vaccination and resolve relatively quickly.
If someone develops a completely different illness weeks or months later, that doesn’t automatically mean the vaccine caused it.
The timing, symptoms, medical history, and other possible causes all need to be considered.
9. Rare Serious Vaccine Reactions Are Possible
Like other medicines and vaccines, COVID-19 vaccines can have rare serious adverse events.
For example, myocarditis and pericarditis have been associated rarely with COVID-19 vaccination, with the highest observed risk occurring in certain adolescent and young adult males.
Anyone who develops chest pain, shortness of breath, or a fast or pounding heartbeat after vaccination should seek medical evaluation. CDC
Recognizing a rare adverse event is different from claiming that vaccination generally causes people to become chronically ill.
10. Long COVID Can Still Occur After Breakthrough Infection
Vaccination doesn’t make a person completely immune to Long COVID.
A vaccinated person who subsequently becomes infected can still develop persistent symptoms.
However, CDC reports that people who are vaccinated and later develop COVID-19 are less likely to develop Long COVID than people who are unvaccinated or not up to date with vaccination. CDC
11. A Positive Test After Vaccination Doesn’t Prove the Vaccine Failed
Imagine two vaccinated people who become infected.
One experiences a mild sore throat and fatigue for several days and recovers at home.
Another person with multiple risk factors develops pneumonia and requires hospitalization.
Both had infections, but vaccination can influence the severity and outcome of those infections.
That’s why vaccine effectiveness is measured using several outcomes, including symptomatic infection, emergency visits, hospitalization, critical illness, and death. CDC
12. Don’t Ignore Serious Symptoms
Whether someone is vaccinated or unvaccinated, serious COVID-19 symptoms require medical attention.
Seek urgent medical help for symptoms such as:
- Severe difficulty breathing
- Persistent chest pain or pressure
- New severe confusion
- Difficulty waking or staying awake
- Other rapidly worsening symptoms
A person’s vaccination status should never be used to dismiss serious symptoms.
What This Really Means
The statement “vaccinated people can still get sick” is true, but it needs context.
Vaccination isn’t designed to create an impenetrable barrier that makes infection impossible. Protection varies with the vaccine, time since vaccination, age, health conditions, previous infection, and circulating variants. CDC
The more important finding is that COVID-19 vaccination reduces the risk of serious outcomes, particularly hospitalization and critical illness. CDC
Final Takeaway
A vaccinated person can still catch COVID-19, experience symptoms, and in some cases develop Long COVID. That does not by itself demonstrate that vaccination caused the illness or that vaccination provides no benefit.
If someone develops persistent or concerning symptoms after vaccination or after a COVID-19 infection, the best approach is to have those symptoms evaluated individually rather than assuming the cause.
