Uncommon Presentation of COVID-19 With Long Incubation Period and Only Gastrointestinal Symptoms in a Fully Vaccinated Patient: Is There a Relation?

Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease that caused a worldwide pandemic in December 2019. It affected millions of people across the world and forced nations to lockdown their borders and implement curfews to control the spread of the disease. Unusual manifestations of the disease should be reported and be kept in mind among physicians. We report a case of a 33-year-old man who was fully vaccinated with two doses of Pfizer vaccine and presented with fever, epigastric pain, and diarrhea without any respiratory symptoms. The patient had a longer than usual incubation period of 16 days without reporting any signs of respiratory infection for the period of his infection. His laboratory investigations and chest X-ray were all normal. The patient did not require any treatment and his COVID-19 infection lasted for 10 days. Clinicians should understand that post-vaccination COVID-19 cases might present with a longer incubation period than usual and might present with gastrointestinal symptoms as the sole complaint.