As if the Delta variant weren’t unpredictable enough, now it appears the COVID-19 virus can produce different symptoms depending on your vaccination status.

Researchers using the ZOE COVID Symptom study, which tracks symptoms using an app of both the vaccinated and unvaccinated, found these five most common symptoms reported by vaccinated people:

  1. Headache.
  2. Runny nose.
  3. Sneezing.
  4. Sore throat.
  5. Loss of smell.

The doctors and scientists from Massachusetts General Hospital, Harvard’s T.H. Chan School of Public Health and health science company ZOE who created the app found these five most common symptoms reported by unvaccinated people:

  1. Headache.
  2. Sore throat.
  3. Runny nose.
  4. Fever.
  5. Persistent cough.

A persistent cough, among other symptoms, was more likely reported by people who had received only one dose of the two-dose Pfizer-BioNTech or Moderna vaccines or were unvaccinated, the researchers said. Shortness of breath, a common symptom of early COVID-10 strains, now ranks 30th among reported symptoms.

But how do you tell if these symptoms are related to COVID-19, flu, the common cold or seasonal allergies? You don’t.

“I wouldn’t even try,” says Dr. Ulysses Wu, Hartford HealthCare’s System Director of Infection Disease and Chief Epidemiologist. “If you are experiencing any symptoms, whether you are vaccinated or not vaccinated, the suggestion would be to test.”

Dr. James Cardon, Hartford HealthCare’s Chief Clinical Integration Officer, said all drive-through testing facilities have closed but testing is readily available across the state, including Hartford HealthCare-GoHealth Urgent Care Centers and, for Hartford HealthCare patients with orders provided by their physician, more than 100 Quest Diagnostics locations

“We still have plenty of testing availability throughout all the communities we serve,” he says.