First use of mRNA COVID vaccine to treat persistent SARS-CoV-2 infection
A new case report published in the Journal of Clinical Immunology has presented the first description of a mRNA COVID-19 vaccine being used to therapeutically treat a patient experiencing a persistent SARS-CoV-2 infection. The immunocompromised patient, who repeatedly tested positive for SARS-CoV-2 for well over six months, was seen to finally clear the virus from his system following two doses of an mRNA vaccine.
Viral infections are usually characterized as either acute or chronic. Chronic viral infections, such as herpes or the Epstein-Barr virus, are often undetectable for long periods of time. The virus can sit dormant for years, occasionally reactivating and leading to physiological symptoms and new waves of infectiousness.
In some rare cases, those with weakened immune systems can experience a form of chronic viral infection known as a persistent infection. In these instances a virus can remain acutely active for months with the patient consistently experiencing negative symptoms and shedding infectious viral particles.
A new study from researchers in the UK reports on the case of a 37-year-old man named Ian Lester who experienced a persistent SARS-CoV-2 infection, consistently delivering positive PCR tests for 218 days. Lester has a rare genetic disease called Wiskott-Aldrich syndrome, and initially he displayed very mild COVID-19 symptoms.
“Although most people are able to stop isolating after 10 days of contracting the virus, I was an exception to the rule,” said Lester. "Each test came back positive, time and time again. Months passed, which felt like a lifetime when you’re not able to go anywhere or see friends or family.”
Over time, Lester’s symptoms worsened as he returned positive PCR tests every fortnight. Blood tests five months into the infection showed no SARS-CoV-2 antibodies, indicating his immune system had not at all responded to the invading coronavirus. Stephen Jolles, clinical lead at Cardiff University, figured it was time to try a more experimental treatment.
“Given the persistent positive PCR tests and impact on his health and mental health, we decided on a unique therapeutic approach,” said Jolles. “We wondered whether therapeutic vaccination could help in finally clearing the virus by inducing a strong immune response within the body.”
The team gave Lester two doses of Pfizer’s mRNA COVID-19 vaccine, separated by about four weeks. Within 14 days of the first dose PCR testing indicated a distinct decrease in the volume of viral material gathered during each nasopharyngeal swab. About six weeks after the second dose Lester tested negative to SARS-CoV-2 for the first time 218 days.
“It was a pretty astonishing moment,” said Mark Ponsford, another clinician working on the case. “To our knowledge, this is the first time mRNA vaccination has been used to clear persistent COVID-19 infection. Importantly, the vaccine was well tolerated by the patient and successfully induced a strong antibody and T-cell response. This was remarkable given Ian’s response to conventional vaccinations in the past has been extremely limited.”
The case study is a compelling example of how mRNA vaccines could be used for therapeutic purposes alongside more traditional prophylactic approaches. Therapeutic vaccines can help prompt the immune system to target a pre-existing disease and much research is currently focused on therapeutic vaccines to target a variety of cancers.
The new study was published in the Journal of Clinical Immunology.
Source: Cardiff University