Razi Cov Pars

The persistent emergence of COVID-19 variants and recurrent waves of infection worldwide underscores the urgent need for vaccines that effectively reduce viral transmission and prevent infections. Current intramuscular (IM) COVID-19 vaccines inadequately protect the upper respiratory mucosa. In response, we have developed a nonadjuvanted, IFN-armed SARS-CoV-2 fusion protein vaccine with IM priming and intranasal (IN) boost sequential immunization. Our study showed that this sequential vaccination strategy of the IM+IN significantly enhanced both upper respiratory and systemic antiviral immunity in a mouse model, characterized by the rapid increase in systemic and mucosal T and B cell responses, particularly the mucosal IgA antibody response. The IN boost triggered a swift secondary immune response, rapidly inducing antigen-specific IgA+ B cells. Further B cell receptor-seq (BCR-seq) analysis indicated that these IgA+ B cells primarily arose through direct class switching from preexisting IgG+ B cells in draining lymph nodes. Notably, our clinical studies revealed that the IN boost after IM vaccination elicited a robust systemic IgA antibody response in humans, as measured in serum. Thus, we believe that our cytokine-armed protein vaccine presents a promising strategy for inducing rapid and potent mucosal protection against respiratory viral infections.

Heterologous vaccines enhance the immune response to new variants and allow flexibility in booster administration when the original vaccine is unavailable. Studies show that heterologous boosters can generate comparable or superior antibody responses compared to homologous boosters. Considering rare side effects is essential in evaluating COVID-19 vaccines, especially those associated with ChAdOx1-S (AstraZeneca) and Ad26.COV2.S (Janssen), including blood clotting and idiopathic thrombocytopenia. Severe side effects, such as myocarditis and pericarditis, may occur after Pfizer or Moderna boosters but are rare.

This study administered two vaccines: the Sinopharm inactivated virus vaccine and the Razi-CoV-Pars (RCP) booster. Various evaluations included biochemical markers, coagulation factors, autoimmune antibodies, and antibodies against concerning variants.

All 90 participants exhibited a notable rise in antibody levels against the variant of concern (VOC). Participants receiving the Razi-CoV-Pars booster after Sinopharm/BBIBP-CorV showed significantly higher antibody levels (Wuhan ∼ 3.25 times, Delta ∼4 times, Omicron ∼ 14 times) compared to those receiving Sinopharm's homologous vaccine. No significant changes (P: <0.05) were found in LDH, CPK, CK-MB, ANA, and Anti-CCP levels. However, individuals receiving Sinopharm's booster after two doses showed a significant increase (4 cases) in D-Dimer levels.

The Razi-CoV-Pars vaccine demonstrates a favorable safety profile and promising potential as an effective booster against current variants, particularly due to its significant protective titer against Omicron.