More than 180 million people have been infected by SARS-CoV-2 and more than 4 million COVID-19 patients have died during the pandemic. Due to the complex pathological lesions in the lungs and multiple organs, the survivors of severe disease often result in disabling sequels.
A great effort is ongoing to mitigate the pandemic at an international level by the diagnosis and isolation of SARS-CoV-2 infected patients and the introduction of new vaccines. However, the access to vaccines in some countries is still limited, and treatments have shown very limited efficacy.
Information available indicates that host immunity may be an important determinant of the outcome, with evidence regarding the role of host immunity becoming clear because elderly people with compromised immunity of those with comorbidities are prone to develop severe disease.
It is recognized that the induction of mucosal immunity may shut the door on SARS-CoV-2 by preventing initial steps of infection.
HeberNasvac Vaccine Use
A group of researchers from Cuba evaluated the use of NASVAC as a postexposure prophylaxis treatment in a cohort of suspected and SARS-CoV-2 risk-contact patients.
HeberNasvac is a novel therapeutic vaccine for chronic hepatitis B (CHB) that is already approved for use in Cuba, while also being confirmed safe and efficacious in a study in Japan. Recently it’s being used for SARS-CoV-2 postexposure prophylaxis.
The group consisted of a total of 46 patients, 60 years or older, presenting with symptoms of COVID-19. They received NASVAC (100 micrograms Ag per dose) via intranasal administration at days 1, 7, and 14, and sublingual daily for 14 days.
The researchers found that the tonsils of patients after the treatment had an increased expression of toll-like receptors (TLR)-related genes (TLR3, TLR7, and TLR8), a relevant property considering these are markers of SARS protection in the mice model of lethal infection. NASVAC was safe and well tolerated. They also observed that patients had a reduction in the number of days with symptoms.
They concluded that the study justified the use of NASVAC as a preemptive therapy or pre/postexposure prophylaxis of SARS-CoV-2 and acute respiratory infections in general due to its active principles and potential immunomodulatory properties.
Yoel A. Fleites, et al. HeberNasvac, a Therapeutic Vaccine for Chronic Hepatitis B, Stimulates Local and Systemic Markers of Innate Immunity: Potential Use in SARS-CoV-2 Postexposure Prophylaxis. 2021. Euroasian J Hepatol-Gastroenterol. 11(2): 59–70. doi: 10.5005/jp-journals-10018-1344