Researchers at the Department of Microbiology and the State Key Laboratory of Emerging Infectious Diseases, LKS Faculty of Medicine at the University of Hong Kong (HKUMed) have conducted a comprehensive study to identify an effective vaccine regimen to prevent SARS-CoV-2 nasal infection. The study showed that a combination of intramuscular PD1-based receptor binding domain (RBD) DNA vaccine (PD1-RBD-DNA) prime and intranasal live attenuated influenza-based vaccine (LAIV-HK68-RBD) boost vaccination program induced the strongest mucus broadly neutralizing antibodies and pulmonary memory CD8 T cells, which prevented living SARS-CoV-2 nasal challenges in two animal models. The entire research article is now online in the journal for EBioMedicine, published by The Lancet.
The COVID-19 pandemic has resulted in over 275 million infections with nearly 5.36 million deaths over time, yet few vaccines approved for emergencies can induce adequate mucosal protection to prevent robust SARS-CoV-2 nasal infection. Although current vaccination significantly reduced the number of hospitalizations, severity, and deaths, these vaccines are much less effective in preventing SARS-CoV-2 respiratory transmission, which has posed major challenges for pandemic control. With the continuous emergence of SARS-CoV-2 variants of concern, including the rapid spread of the immunoscape Omicron strain, it is urgent to find a more effective vaccine strategy to block or reduce nasal transmission of SARS-CoV-2.
Research methods and findings
In this HKUMed study, significantly higher systemic and mucosal antibodies IgA / IgG and lung resident polyfunctional memory CD8 T cells were primarily induced by the heterologous combination regimen compared to current COVID-19 vaccination regimens. When two vaccinated mouse models were challenged in the memory phase, 35 days after the second vaccination, prevention of robust SARS-CoV-2 infection in nasal turbinate was achieved primarily by the heterologous combination regimen in addition to consistent protection in the lungs. The new regime-induced antibodies also cross-neutralized many pandemic variants of concern, including alpha, beta, and delta. The results provided proof-of-concept that vaccine-induced robust mucosal immunity is necessary to prevent SARS-CoV-2 nasal infection, which is essential for ending the ongoing COVID-19 pandemic.
The significance of the study
“The results indicated that the clinical development of our two HKU vaccines remains a top priority to eliminate the uncontrolled spread of the COVID-19 pandemic. We are currently testing the influenza-based nasal spray vaccine and the DNA vaccine in humans,” noted Professor Yuen Kwok. -yung, Henry Fok Professor of Infectious Diseases and Chairman of Infectious Diseases, Department of Microbiology, HKUMed, who is currently leading the clinical trials of these two vaccines in Hong Kong.
“The biggest challenge for our COVID-19 vaccine development is that we do not have a vaccine factory in Hong Kong, which has delayed the translation of scientific discoveries for clinical use. Now we face the same challenge after we already have made Omicron-targeted DNA vaccine for timely clinical development, “said Professor Chen Zhiwei, Director of the AIDS Institute, Professor of the Department of Microbiology, HKUMed, who helped lead the research.
“We believe that the use of nasal spray vaccination to build upper respiratory protection is the key strategy for reducing SARS-CoV-2 transmission and important for the ultimate control of the COVID-19 pandemic,” said Professor Chen Honglin, Professor at the Department. for Microbiology, HKUMed, who helped lead the research.
Nasal vaccine can help fight new viral variants
Runhong Zhou et al, Nasal prevention of SARS-CoV-2 infection by intranasal influenza-based boost vaccination in mouse models, EBioMedicine (2021). DOI: 10.1016 / j.ebiom.2021.103762
Provided by the University of Hong Kong
Citation: Research Team Detects New Vaccine Strategy to Prevent SARS-CoV-2 Nasal Infection (2021, December 30) Retrieved December 30, 2021 from https://medicalxpress.com/news/2021-12-team-vaccine-strategy-sars – cov-nasal.html
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