Nanoparticle Vaccine Image
An electron microscopy image of lymph node tissue from a mouse that was immunized with an experimental COVID-19 vaccine. (Credit: Yi-Nan Zhang, Kimberly Vanderpool, Theresa Fassel, and Scott Henderson.)

A nanoparticle-based COVID-19 vaccine has elicited immune responses suggesting very potent and broad protection against SARS-CoV-2 in a preclinical study. The results need to be confirmed in human trials but point to the possibility of achieving powerful and enduring immunity against all major SARS-CoV-2 variants.

The experimental vaccine does not use viruses, messenger RNA, or loose copies of the SARS-CoV-2 spike protein, and instead is made from proteins that self-assemble into virus-like nanoparticle structures.

In mice, the researchers found, these nanoparticle structures elicit immune responses that powerfully neutralize the original Wuhan strain of SARS-CoV-2, and — with the same potency — all the other major variants of concern including the fast-spreading delta variant.

The self-assembling nanoparticle design is one that the researchers have used in recent years for other candidate vaccines, including for HIV, hepatitis C virus, and Ebola virus. It features a nanoparticle sphere of protein into which smaller proteins that mimic the virus’s outer spike proteins embed themselves.

The study thus suggests that the nanoparticle-based design, if eventually approved for use after clinical trials could greatly outperform other COVID-19 vaccines in terms of the potency of protection, the breadth of protection, and perhaps also the duration of protection.