Approved vaccine boosts against SARS-CoV-2 injected via the intramuscular route continue to protect against severe COVID-19 disease. However, mRNA or adenovirus vector-based vaccines administered via the intramuscular route do not elicit mucosal immunity, limiting their ability to prevent SARS-CoV-2 transmission and infection. In a new study, a team of researchers compared protection against SARS-CoV-2 in nonhuman primates following intramuscular boosting with an mRNA vaccine or mucosal boosting with an adenoviral-vectored vaccine delivered by intranasal or aerosol devices. They found that immunity induced by the mucosal vaccine was durable over a period of 5 months, in contrast to the rapid peak and subsequent waning typical of intramuscular vaccination with mRNA vaccines. In addition, the mucosal vaccine elicited durable airway IgG and IgA responses and, unlike the intramuscular mRNA vaccine, induced spike-specific B cells in the lungs. These findings could guide the development of next-generation vaccines to prevent the transmission of SARS-CoV-2 and other respiratory pathogens.

Original reference: Gagne, M. et al. Nat. Immunol. https://doi.org/10.1038/s41590-024-01951-5 (2024)

经批准通过肌肉注射途径注射的 SARS-CoV-2 疫苗加强疫苗可继续预防严重的 COVID-19 疾病。然而，通过肌肉注射途径施用的基于 mRNA 或腺病毒载体的疫苗不会引发粘膜免疫，从而限制了它们预防 SARS-CoV-2 传播和感染的能力。在一项新的研究中，一组研究人员比较了非人灵长类动物在肌内加强注射 mRNA 疫苗或粘膜加强疫苗与通过鼻内或气雾剂装置输送的腺病毒载体疫苗后对 SARS-CoV-2 的保护作用。他们发现，粘膜疫苗诱导的免疫力可以持续 5 个月，这与 mRNA 疫苗肌肉注射疫苗接种典型的快速峰值和随后减弱形成鲜明对比。此外，粘膜疫苗引发了持久的气道 IgG 和 IgA 反应，并且与肌内 mRNA 疫苗不同的是，它在肺部诱导了刺突特异性 B 细胞。这些发现可以指导下一代疫苗的开发，以防止 SARS-CoV-2 和其他呼吸道病原体的传播。

Original reference: Gagne, M. et al. Nat. Immunol. https://doi.org/10.1038/s41590-024-01951-5 (2024)