Following the case of an unvaccinated elderly woman who was found to be infected with both the alpha and beta variants of Covid-19, experts believe it is possible to be infected with two different strains of the coronavirus at the same time.

In March, the 90-year-old woman died in a hospital in Belgium. The case study was presented this weekend at the European Congress of Clinical Microbiology and Infectious Diseases, and experts believe it is the first known case of a double infection, emphasizing the importance of being aware of the possibility.

The woman, whose medical history was unremarkable, had been admitted to hospital in Aalst, Belgium, in early March after a series of falls, according to experts. On the same day, she tested positive for Covid-19 and began experiencing rapidly worsening respiratory symptoms. She passed away five days later. The woman’s genome sequencing confirmed she was infected with the two variants.

It’s unclear how or when the woman, who lived alone and received home nursing care, became infected. She had not received a Covid-19 vaccination. According to studies, the main vaccines used in the United States and Europe (the Pfizer-BioNTech, Moderna, and AstraZeneca-University of Oxford shots) are effective against the Covid variants that have emerged, preventing the majority of hospitalizations and deaths.

“This is one of the first documented cases of co-infection with two SARS-CoV-2 variants of concern,” said Dr Anne Vankeerberghen, lead author of the case report and molecular biologist at Aalst’s OLV Hospital.

She explained that because both variants were circulating in Belgium at the time, the woman was most likely infected by two different people. “Whether the co-infection of the two variants of concern played a role in the fast deterioration of the patient is difficult to say,” Vankeerberghen added. “Up to now, there have been no other published cases. However, the global occurrence of this phenomenon is probably underestimated due to limited testing for variants of concern and the lack of a simple way to identify co-infections with whole genome sequencing.”

Scientists in Brazil reported in January 2021 that two people had been infected with two different strains of the coronavirus — the gamma variant first identified in Brazil and a variant currently under investigation discovered in Rio Grande do Sul — but the study has yet to be published in a scientific journal. Previous studies have found people infected with various influenza strains.

As the coronavirus pandemic progressed, a number of variants emerged that proved to be far more transmissible than the “original” strain of Covid, which emerged in China in late 2019. The alpha variant, for example, was discovered in southeast England last fall and quickly spread throughout the world. It is now being supplanted by the extra-infectious delta variant, which was discovered in India in April. In December, another variant, known as the beta variant, emerged in South Africa.

According to the World Health Organization’s most recent weekly epidemiological report, published on July 6, the alpha variant has now been reported in 173 countries, territories, or areas, and the beta variant in 122. Delta has been found in 104 countries so far.