The SARS-CoV-2 virus has mutated numerous times over the course of the COVID-19 pandemic. Unfortunately, some of its altered forms—especially variants of concern (VOCs)—are more lethal than the original strain that emerged in Wuhan. In an unusual occurrence, scientists have reported the co-infection of two VOCs in a 90-year-old woman.
According to a new case study set to be presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), Belgian scientists report the case of a 90-year-old woman who was infected simultaneously by two different—Alpha variant (B.1.1.7-UK) and Beta variant (B.1.351-South Africa). The scientific article describing all the findings in detail is yet to be published.
"This is one of the first documented cases of co-infection with two SARS-CoV-2 variants of concern. Both these variants were circulating in Belgium at the time, so it is likely that the lady was co-infected with different viruses from two different people. Unfortunately, we don't know how she became infected," said Dr. Anne Vankeerberghen, lead author of the study, in a statement.
Variants of Concern
As of May 2021, the World Health Organization (WHO) has categorized four variants of the SARS-CoV-2 as VOCs. Along with Alpha and Beta variants, the Delta (B.1.617.2-India) and Gamma (P.1-Brazil) variants complete the list. These VOCs are more potent than the original virus and have higher infectivity. The 'spike' (the protein structure that the virus uses to invade cells) has emerged as the hotspot for all mutations that make variants more virulent.
The nonagenarian was admitted to the OLV Hospital in the city of Aalst, Belgium on 3 March 2021, after suffering a series of falls. Prior to her admission, the elderly woman did not have a medical history of concern. She tested positive for COVID-19 on the day of her admission. Receiving nursing care at home, she lived alone and was not vaccinated against SARS-CoV-2.
She showed no signs of respiratory stress initially and her oxygen saturation levels were optimum. However, her respiratory symptoms worsened drastically, and she succumbed to the infection five days later. Following her demise, the doctors tested her respiratory samples for VOCs using a PCR (polymerase chain reaction) test.
Infected With Multiple VOCs
It was discovered that the 90-year-old has been infected with two different VOCs—Alpha and Beta Variants. By conducting PCR tests on a second respiratory sample, the presence of both the lethal strains was confirmed. The S-gene and the whole genome of the viruses were also sequenced to confirm the variants.
"Whether the co-infection of the two variants of concern played a role in the fast deterioration of the patient is difficult to say. 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," expressed Dr. Vankeerberghen.
Rare Yet Concerning
While the case of the nonagenarian's simultaneous infection by two different strains is rare, it is not the first known instance. In January 2021, researchers in Brazil announced that two individuals had been infected with two separate variants of the novel coronavirus—a Brazilian variant B.1.1.28 (E484K) and a novel variant known as novel variant VUI-NP13L. However, the study has not been published in a scientific journal yet.
Dr. Vankeerberghen stressed that irrespective of the technique employed, it is important to remain vigilant and spot co-infections. "Since co-infections with variants of concern can only be detected by VOC-analysis of positive samples, we would encourage scientists to perform fast, easy and cheap VOC-analysis by PCR on a large proportion of their positive samples, rather than just whole genome sequencing on a small proportion," she emphasized.