Since the emergence of the coronavirus disease (COVID-19) in December 2019, cases of reinfections have been reported worldwide. It is still unclear if being infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will provide long-lasting immunity. Still, scientists hope it would be the case so vaccines can work efficiently.
Of the cases of reinfections worldwide, a particular case has been reported by scientists at the Nevada Institute of Personalized Medicine, University of Nevada. A 25-year-old man from Washoe County in the United States, the hardest-hit country globally, has more than 7.85 million cases.
Transmission electron micrograph of SARS-CoV-2 virus particles, isolated from a patient. Image captured and color-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Credit: NIAID
A case of reinfection
The patient presented to a community testing event held by the Washoe Country Health District on April 18 with symptoms of cough, sore throat, nausea, headache, and diarrhea that started on March 25. The patient had no history of any underlying health conditions, and during isolation, his symptoms improved. He recovered by April 27.
The patient went back to his daily activities and continued to feel well until May 28. On May 31, the patient sought medical assistance at an urgent care center due to headache, fever, dizziness, cough, nausea, and diarrhea. He was eventually discharged after a chest X-ray. However, five days later, the patient became hypoxic with difficulty breathing and was instructed to go to the emergency department for further assistance.
Two positive tests
On each occurrence of his symptoms, he had nasopharyngeal swabs. He also underwent testing twice during follow-up. To determine if the illness can be attributed to just one strain of the coronavirus, the team assessed sequence data by two different bioinformatic methodologies.
The first nasopharyngeal swab obtained at the community screening event in April tested positive for SARS-CoV-2 on real-time RT-PCR testing. The two follow-up tests turned out negative. When the patient’s symptoms recurred in May, the specimen turned out positive for SARS-CoV-2 infection.
The second bout was worse as the patient needed ongoing oxygen support in the hospital. The chest radiography results showed patchy, bilateral, and interstitial opacities that hint viral or atypical pneumonia. Further, on June 6, the patient was tested for SARS-CoV-2 antibodies, and the results turned out positive, which means he had been infected with the virus.
Since the patient had two episodes of symptoms consistent with COVID-19, with positive tests separated by as much as 48 days, the case may be considered reinfection.
“Our findings have implications for the role of vaccination in response to COVID-19. If we have truly reported a case of reinfection, initial exposure to SARS-CoV-2 might not result in a level of immunity that is 100% protective for all individuals,” the authors wrote in the paper.
“With respect to vaccination, this understanding is established, with influenza regularly showing the challenges of effective vaccine design,” they added.
Understanding the mechanism of infection and if reinfection can occur are vital in developing effective vaccines. This way, they have a better understanding of the possibility of reinfection in some patients who have already recovered from COVID-19.
The case study is published in The Lancet.
COVID-19 is raging across the globe, making it more critical that vaccines become ready as soon as possible. Some countries who have flattened the curve have reported second waves of the infection.
The global case toll has reached more than 38 million cases, with at least 1 million people dead from SARS-CoV-2 infection. The United States reports the highest number of cases, with more than 7.85 million infections, followed by India, with at least 7.17 million confirmed cases.
Other countries that report high infections include Brazil, with more than 5.11 million cases, Russia, with more than 1.31 million cases, and Colombia with more than 924,000 cases.
With the alarming number of cases globally, the race in finding an effective vaccine against COVID-19 is on, with more than 200 vaccine candidates. More than 40 are now undergoing clinical evaluation, while ten are now in phase III of vaccine trials.