Longest-Known COVID Infection Lasts 505 Days

Source: Freepik

A patient at a London hospital tested positive for SARS-CoV-2 for 505 days, becoming the longest-known COVID infection.  

In this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), UK researchers reported the case of a patient that tested positive for 505 days before dying. Thus, becoming the longest-known COVID infection to date.

According to the researchers, the immunocompromised individual first developed COVID-19 in early 2020. Over the next 72 weeks, they underwent multiple hospitalizations, testing positive each time. Moreover, genetic sequencing helped confirm it as a persistent infection and not reinfection. Despite treatment with antiviral drugs, the patient passed away in 2021. However, it is unclear as to what caused the death.

These were throat swab tests that were positive each time. The patient never had a negative test. And we can tell it was one continuous infection because the genetic signature of it — the information we got from sequencing the viral genome — was unique and constant in that patient.

Dr. Luke Blagdon Snell, study author

The patient was part of a larger study comprising nine other individuals that tested positive for at least 8 consecutive weeks. All patients had a weakened immune system due to HIV, cancer treatment, organ transplants, or some other illness. Between March 2020 and December 2021, researchers in London analyzed their samples for genetic changes within the virus. According to the results, the average duration of infection was 73 days.

Moreover, the study authors also reported the first case of occult infection. According to researchers, occult infection is the persistence of infection in someone thought to have cleared the pathogen. In this case, the patient initially contracted the Alpha variant, recovered, tested negative, and then later tested positive again for the same strain. Thus, the study authors believe that the virus likely remained hidden in the patient’s body since the first infection.

Weakened Immune Systems and Viral Mutation

The team of researchers aimed to investigate whether immunocompromised individuals with prolonged COVID infections give rise to variants. As part of the study, the team conducted a genetic analysis of the samples each time the patients underwent testing. Out of the nine patients, five developed at least one mutation present in variants of concern like Alpha, Delta, and Omicron. These mutations affected the spike protein of the virus that helps the virus enter cells. Furthermore, a viral sample from one patient demonstrated ten mutations that would arise separately in variants of concern. This suggests that prolonged infections in immunocompromised individuals give the virus more chances to adapt and change. As a result, mutations give rise to new variants.

This provides evidence that mutations found in variants of concern do arise in immunocompromised patients and so supports the idea that new variants of the viruses may develop in immunocompromised individuals.

Dr. Luke Blagdon Snell, study author

However, none of the individuals in the study developed any new variants that became variants of concern. Nor is there evidence of them spreading the virus to others. Nevertheless, the study signifies the need for better treatments for immunocompromised individuals susceptible to persistent infections, to prevent the emergence of variants.

Out of the nine study patients, four eventually died. Of the remaining five, two cleared the infection after treatment with antibody therapies and antivirals. While other two did not require any treatment. One person continues to remain infected and has had the infection for more than 400 days now. Doctors believe they could form a new record for the longest COVID infection.

Previous Longest COVID Infection Record Held by Maryland Woman

A 47-year-old woman from Maryland held the previous record for the longest COVID infection. The cancer survivor tested positive for a record 335 days, a little shy of a year. According to the study, the woman first developed symptoms in 2020. Although the symptoms were initially mild, over time her cough and shortness of breath worsened to the extent of hospitalization.  

Laboratory examinations revealed alternating viral load levels within her blood sample. Thus, causing doctors to suspect an infection with another strain. Moreover, they also suspected nonviable viral fragments of causing the patient’s continuous positive tests. It wasn’t until they conducted genomic sequencing of her original samples and those collected ten months later that they discovered the truth.

Genomic sequencing revealed the virus in both samples as similar. However, they did not two genetic deletions with the virus. Thus, providing evidence of the virus mutating within immunocompromised individuals and ultimately leading to the emergence of new variants.

Immunocompromised patients with persistent infection have poor outcomes, and new treatment strategies are urgently needed to clear their infection. This may also prevent the emergence of variants.

Dr Gaia Nebbia, study co-author

The cancer survivor had received CAR-T cell therapy 3 years prior to her infection. The low levels of B cells within her blood likely caused the prolonged infection. These cells help produce antibodies and evoke an immune response in individuals.

Although prolonged infections are rare, certain people are more at risk and can develop severe COVID-19. Therefore, there is a need for better treatment strategies that can improve outcomes in these patients. And prevent the virus from mutating into new variants.

Source: European Congress of Clinical Microbiology and Infectious Diseases


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