Press release 2023-08-28

ISR’s, SARS-CoV-2 dry powder nasal - vaccine booster candidate, ISR52, demonstrates superior immune response, in mouse model challenge studies compared to subcutaneous injection of this vaccine.

The preclinical SARS-CoV-2 vaccine collaboration project between ISR (Immune System Regulation AB)  and Professor Ali Mirazimi, adjunct professor at the Department of Laboratory Medicine, Karolinska Institutet has now been published in the journal Vaccine.

The mucosal immune system is the largest component of the entire immune system, having evolved to provide protection at the main sites of infectious threat: the mucosae. As SARS-CoV-2 initially infects the upper respiratory tract, its first interactions with the immune system must occur predominantly at the respiratory mucosal surfaces, during both inductive and effector phases of the response. However, all authorised COVID-19 vaccines are administered by injection to focus exclusively on the development of serum antibodies and systemic cell-mediated immunity, including innate responses. ISR believe there is a significant role for mucosal immunity and for secretory as well as circulating IgA antibodies in COVID-19.

When tested in a preclinical challenge study, using an hACE2 transgenic SARS-CoV-2 mouse model, intranasal and intratracheal administration of ISR52 provided superior protection against severe infection, compared to the subcutaneous injection of the same vaccine. Inhaled ISR52 elicited both CD4 and CD8 T-cell spike-specific responses, that were maintained for at least 6-months in wild-type mice. The induced IgG and IgA responses cross-reacting with several SARS-CoV-2 variants of concern were detected in the lung and in serum and protected animals, which displayed neutralizing antibodies.   Based on our results, ISR52 as a dry powder formulation for nasal administration, a product that does not require cold-chain distribution or the use of needle administration, is a good choice for evaluation in a Phase I/II clinical trial.  

We are excited by the publication in Vaccine* of these pre-clinical data of our dry powder nasal vaccine, and next step will be to conduct a  first- in- human clinical trial, likely in a booster setting . We believe there is a great need for an effective, simple to distribute and administer vaccine for booster use in future seasonal waves of SARS-CoV-2 and with subvariants of Omicron circulating:  according to WHO, globally, even with reduced testing some over 868 000 new COVID-19 cases and over 3700 deaths were reported in the period 26 June to 23 July 2023.  says Ola Winqvist,  CEO at ISR AB


For more information, please contact:
Ola Winqvist, CEO, ISR Immune System Regulation Holding AB (publ) Email:

About ISR

About ISR Immune System Regulation Holding AB (publ)

ISR is an innovation-driven drug development company in the field of immunotherapy. The company’s business model is to convert promising preclinical immunological research into next generation vaccine products. By stimulating the immune system in conjuction with the administration of a target immunostimulatory immunolids and Immunorhelins molecules, The company aims to fight chronic infections such as HiV, HBV and cancer.

The company has its headquarters in Stockholm.