The 32 Most Common Signs You Have Breakthrough COVID, New Study Says
Fully vaccinated patients may have different symptoms than those who haven't gotten their shots.
There's been very little in the way of good news since the beginning of the COVID-19 pandemic, but the release of highly effective vaccines has provided some hope that there is light at the end of the tunnel. Unfortunately, no vaccine is perfect. Whether it's waning effectiveness over time, the emergence of a new variant, or simply a person's unique response to the shots, even people who have received all of their doses can still catch the virus in rare instances known as breakthrough infections. But the symptoms that are most common among fully vaccinated people who contract COVID-19 can be a bit different from those seen in unvaccinated patients, as one recent study highlights.
In the U.K., people have been using the Zoe COVID Symptom Study app since it launched in 2020 to track their own symptoms. The most recent analysis of the app's data, which was published in The Lancet on Sept. 1, looked at how 971,504 users who reported being fully vaccinated fared between Dec. 8, 2020 and July 4, 2021. The good news? The researchers found that only 0.2 percent of fully vaccinated patients in the study tested positive for COVID. Results also showed that breakthrough infections were twice as likely to be asymptomatic than cases among those who weren't vaccinated.
However, the study still found 906 cases in which fully vaccinated patients tested positive and experienced at least one symptom. Using data collected through the app, the researchers were able to get a better picture of potential warning signs that you've contracted the virus after getting your shots. Read on to see which symptoms were found to be the most common signs of a breakthrough COVID infection.
Fully vaccinated COVID patients reporting the symptom: 0.6 percent
Shedding your locks has been documented as one of the more surprising effects of COVID-19 since the earlier days of the pandemic. However, less than one percent of people with breakthrough infections reported unusual hair loss as a symptom.
Blisters on feet
Fully vaccinated COVID patients reporting the symptom: 0.8 percent
Some may remember "COVID toes" as one of the strange symptoms of the virus that was reported last spring—particularly among children and teens—but it's seemingly even less common with a breakthrough infection. Just under one percent of respondents in the Zoe study reported experiencing "red [or] purple sores or blisters" on their feet, including their toes.
Red welts on face or lips
Fully vaccinated COVID patients reporting the symptom: 1.6 percent
Some symptoms may be easy to miss, but others can literally stare you right in the face. In the case of the Zoe study, just 14 respondents said they experienced "raised, red, itchy welts on the skin or sudden swelling of the face or lips," accounting for less than 2 percent of breakthrough COVID patients.
Rash on arm or torso
Fully vaccinated COVID patients reporting the symptom: 2.8 percent
It's not just a reaction on your feet and face that can be a sign of a breakthrough COVID infection. Nearly three percent of respondents in the study reported a rash on their arms or torso as a symptom.
For comparison, a self-organized group of coronavirus patients online from the Body Politic COVID-19 Support Group did a survey to determine the most common COVID symptoms before vaccines were administered. Among the 640 COVID patients surveyed, 17.9 percent experienced a skin rash.
Sensation of skin burning
Fully vaccinated COVID patients reporting the symptom: 5.9 percent
In some breakthrough cases, your skin can have a different reaction that's just as uncomfortable. Nearly six percent of respondents in the study reported feeling "strange, unpleasant sensations in your skin like 'pins & needles' or burning" after becoming infected. In the 2020 survey of COVID patients, 24 percent felt a similar tingling sensation on the their skin.
Fully vaccinated COVID patients reporting the symptom: 6.2 percent
If you suddenly notice an irregular heartbeat when you're fully vaccinated, it could be a sign you've got a breakthrough COVID infection, one more than 6 percent of patients reported in the Zoe study.
Still, that's far lower than the 36.2 percent of patients in 2020, pre-vaccinations, who reported experiencing tachycardia (or rapid heart beat), or the 56.7 percent who had elevated pulses or heart rates.
Delirium or reported confusion
Fully vaccinated COVID patients reporting the symptom: 6.7 percent
It's become well known that COVID-19 can cause some psychological effects. In the case of those who are fully vaccinated, feelings of "confusion, disorientation, or drowsiness" were reported by nearly 7 percent of respondents. For comparison, 28.8 percent of respondents who had COVID before they were vaccinated reported experiencing hallucinations in the 2020 survey.
Fully vaccinated COVID patients reporting the symptom: 9 percent
A stomachache can also be a sign of a breakthrough COVID infection: Nine percent of respondents reported feeling some kind of abdominal pain during the course of their illness.
While it's not a one-to-one comparison, the 2020 survey grouped all gastrointestinal issues together, and they found that a much higher rate of COVID patients who were not vaccinated—74.6 percent—had stomach problems.
Fully vaccinated COVID patients reporting the symptom: 9.8 percent
If you think you may have a breakthrough infection, an earache might be a red flag. According to the Zoe study, nearly 10 percent of the fully vaccinated people who tested positive for COVID listed an earache as a symptom. That's about a third of the 32.8 percent who reported the symptom in the 2020 COVID survey.
Fully vaccinated COVID patients reporting the symptom: 10 percent
Notice a ringing in your ears? It could be a sign of a breakthrough infection. One in ten fully vaccinated respondents in the Zoe COVID study reported tinnitus as a symptom.
Interestingly, tinnitus had previously been linked to long COVID. A U.K. study from July 2020 surveyed 121 adults who had been hospitalized for severe COVID, and 13 percent of them reported hearing loss and/or tinnitus two months after being discharged.
Fully vaccinated COVID patients reporting the symptom: 10.4 percent
Gastrointestinal issues can be the result of a stomach bug or food poisoning, but they could also potentially be caused by COVID. In the case of breakthrough infections, just over 10 percent of respondents reported experiencing diarrhea when they were sick.
It's unclear exactly how many people had this specific stomach problem in the 2020 survey since gastrointestinal issues were grouped together, but this is certainly lower than the nearly 75 percent of COVID patients who had upset stomachs.
Fully vaccinated COVID patients reporting the symptom: 10.8 percent
The COVID-19 pandemic turned any sign of a sniffle into a potential cause for concern, making life especially stressful for people with a cold or those who typically suffer from seasonal allergies. But an increase in typical hayfever symptoms was also found to be relatively common among those with breakthrough infections in the Zoe study, with nearly 11 percent reporting it.
The 2020 survey did not group cold-like symptoms together, so it's not easy to compare, but 36.4 percent of COVID patients last year experienced post-nasal trip, 39.5 percent had sinus pain, and 72.7 percent had a dry cough.
Fully vaccinated COVID patients reporting the symptom: 10.9 percent
Stomach issues have been linked with COVID-19 since the earliest days of the pandemic, one of the most common being nausea. Those who contracted COVID after being vaccinated reported it 11 percent of the time in the Zoe study. But the symptom was cropping up much more pre-vaccinations: 52.2 percent of people in 2020 survey said they experienced nausea.
Fully vaccinated COVID patients reporting the symptom: 11 percent
Scientists are still trying to understand the psychological and neurological effects that contracting COVID-19 can have on people. In the 2020 survey, 68.7 percent of COVID patients were experiencing anxiety, and it appears that these kinds of symptoms can affect people with breakthrough infections, too. According to the Zoe study, 11 percent of respondents reported feeling especially "down, depressed, or hopeless" during their illness.
Shortness of breath
Fully vaccinated COVID patients reporting the symptom: 11.5 percent
Signs of respiratory distress might be one of the most expected signs of COVID-19. When the COVID patients surveyed their symptoms in the spring of 2020, 85.3 percent reported shortness of breath. In the case of breakthrough infections, shortness of breath or difficulty breathing is still an issue but less so, having been reported by just 11.5 percent of patients in the study.
Fully vaccinated COVID patients reporting the symptom: 11.8 percent
Chest pains may be one of the most frightening symptoms to develop since they're associated with major health incidents like heart attacks. But feeling tightness in the area was also very common with COVID early on. The 2020 survey found that 87.1 percent of patients had tightness in their chest. According to the Zoe study, the symptom also affects people with breakthrough infections but less often, with nearly 12 percent of fully vaccinated respondents reporting it during their bout with COVID.
Fully vaccinated COVID patients reporting the symptom: 12.4 percent
Having swollen glands can be a tell-tale sign that your body is fighting something off. It was showing up earlier in the pandemic (32.3 percent of COVID patients in the 2020 survey reported it), and it still appears to be cropping up with breakthrough COVID infections—more than 12 percent of respondents noted the symptom in the Zoe COVID study.
Unusual muscle pain
Fully vaccinated COVID patients reporting the symptom: 14.2 percent
The Zoe COVID study adds to the mounting body of evidence that being fully vaccinated is incredibly effective at preventing serious complications from COVID. However, some of the more common and less severe symptoms were still reported in patients suffering a breakthrough infection, like "unusual strong muscle pains or aches," which more than 14 percent of fully vaccinated patients confirmed experiencing through the app. That's still an improvement from the 2020 survey's findings, when a massive majority—83.5 percent—of patients reported body aches.
Fully vaccinated COVID patients reporting the symptom: 15.6 percent
A loss of appetite is a common symptom for many viruses, but it's another thing when it's strong enough to make you stop eating altogether. Those suffering from breakthrough infections in the study reported skipping meals as a result of their illness in nearly 16 percent of cases, a significant drop from the 63.8 percent who reported this in the 2020 survey.
Fully vaccinated COVID patients reporting the symptom: 16.9 percent
One of the most dreaded symptoms of COVID-19 has become the inability to focus known as "brain fog," especially as a long-term after-effect of the virus. In the 2020, 68.8 percent of COVID patients reported experiencing brain fog before they were vaccinated. Unfortunately, the Zoe study found that even breakthrough infections saw "a loss of concentration or memory" as a relatively common symptom among nearly 17 percent of patients.
Chills or shivers
Fully vaccinated COVID patients reporting the symptom: 17.1 percent
Chills are a hallmark symptom of a severe cold or the flu, and it was also a very common symptom reported in the earlier days of the COVID pandemic. In the 2020 survey, 76.2 percent of patients said they had the chills.
Today, the symptom is still affecting people with breakthrough infections of COVID-19, but at a lower rate. Results found that just over 17 percent of fully vaccinated respondents in the Zoe study reported them.
Fully vaccinated COVID patients reporting the symptom: 17.4 percent
Eye issues were a rare symptom of COVID-19 in the earlier stages of the pandemic: only 29.9 percent of those surveyed in 2020 had eye strain, 11.8 percent reported pink eye, and 26 percent experienced light sensitivity. But it appears that breakthrough infections are causing uncomfortable eye issues relatively frequently. More than 17 percent of fully vaccinated patients listed light sensitivity, excessive tears, or conjunctivitis among their ailments.
Dizziness or lightheadedness
Fully vaccinated COVID patients reporting the symptom: 20 percent
Feeling off-balance while trying to walk can be an alarming sign that something is wrong, and it could be a symptom of COVID, too. Earlier in the pandemic, 60.8 percent of COVID patients reported feeling dizzy, according to the 2020 survey. But the new Zoe study found that only one in five patients suffering a breakthrough infection said they felt dizzy or lightheaded.
Fully vaccinated COVID patients reporting the symptom: 20.5 percent
Not all symptoms of a breakthrough COVID infection can be seen or felt; more than 20 percent of people with breakthrough COVID in the Zoe study noticed their voices becoming hoarse and unusually gravelly. That was seemingly much less common pre-vaccines, since the 2020 survey did not count hoarsness among their top 51 most common symptoms.
Loss of smell
Fully vaccinated COVID patients reporting the symptom: 20.7 percent
Since its symptoms overlap with colds, allergies, and the flu, COVID-19 has been infuriatingly difficult to nail down. But anosmia—the medical term for the loss of the ability to smell—has long been considered one of the easiest ways to distinguish the virus from other ailments.
According to the 2020 survey, 42.9 percent of COVID patients lost their senses of smell before being vaccinated. The Zoe study found that the symptom was reported with breakthrough infections as well, but much less so: about 21 percent of fully vaccinated respondents with COVID lost the ability to smell or taste.
Fully vaccinated COVID patients reporting the symptom: 28 percent
Developing a serious cough is arguably one of the most widely known symptoms associated with COVID-19. In the 2020 survey, 35.6 percent of patients said they had a persistent cough, 38.6 percent had a cough with mucus, and 72.7 percent had a dry cough, which are significant portions.
In the case of the Zoe study, a lower rate—28 percent—of vaccinated respondents who caught COVID said they experienced "coughing a lot for more than an hour or three or more coughing episodes in 24 hours" while ill.
Fully vaccinated COVID patients reporting the symptom: 29.3 percent
A sore throat is a common symptom of many viruses, including COVID-19. In 2020, 69.6 percent of patients said they had this symptom, but in the Zoe study, 30 percent of fully vaccinated patients said they experienced pain in their throat from the sickness. That makes it a common symptom with breakthrough COVID, but still much less common with vaccinated people than with unvaccinated people.
Fully vaccinated COVID patients reporting the symptom: 39 percent
According to data previously reported by the Zoe COVID Symptom Study, patients who have been vaccinated, whether partially or fully, were more likely to report sneezing as a symptom than those who were unvaccinated. The latest study found more evidence that supports the fact that the symptom is common in breakthrough infections, with 39 percent listing it as one of their ailments.
It's one of the rare instances on this list where a symptom was more common among fully vaccinated COVID patients than with unvaccinated patients; in the 2020 survey, 37.5 percent of patients said they were sneezing with COVID before they were vaccinated.
Fully vaccinated COVID patients reporting the symptom: 41.6 percent
Even when they are mild, a headache can be a debilitating symptom to deal with. Unfortunately, with more than 41 percent of breakthrough COVID patients saying they experienced them, they're quite common among those vaccinated patients who still get sick, but still not as common as they were before vaccines came into the picture. In the 2020 survey, 84 percent of patients said they were experiencing headaches.
Fully vaccinated COVID patients reporting the symptom: 43 percent
Whether you just have a slight case of the sniffles or you're very congested, the latest Zoe study found that a runny nose is one of the most common signs that you have a breakthrough COVID infection. A full 43 percent of vaccinated patients reported it to the app during the data collection period. And, like sneezing, this symptom appears to be more common among fully vaccinated people who get COVID. In the 2020 survey, a lower portion—36.4 percent—of COVID patients said they had post-nasal trip.
Fully vaccinated COVID patients reporting the symptom: 43.7 percent
Feeling consistently sapped of energy may be a common symptom of many viruses, but it's especially so for COVID-19. According to the new study's results, just about 44 percent of fully vaccinated patients reported feeling unusually fatigued over the course of their breakthrough infection.
It's a much higher rate than other COVID symptoms fully vaccinated people report, save for one, but that rate is still significantly lower than the 98.4 percent of patients who reported the symptom in the 2020 survey, pre-vaccine rollout.
Fully vaccinated COVID patients reporting the symptom: 61.9 percent
The Zoe study concluded that running a fever was the most common symptom associated with COVID infections in fully vaccinated people, reported by almost two in three respondents.
Interestingly, fevers have remained consistently common throughout the pandemic, both pre- and post-vaccines. In the 2020 survey, 72.4 percent reported seeing elevated body temperatures as a result of COVID.