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New laboratory studies suggest that BioBlock® nasal spray provides protection against all major variants of coronaviruses

New laboratory studies with BioBlock® nasal spray suggest that BioBlock works against all major variants of coronaviruses, which the World Health Organization considers to be of most concern. Including the Delta variant, which is currently widespread in Estonia.

SARS-CoV-2 virus contains spike protein that binds to the ACE2 receptor on the surface of human cells and mediates the adsorption and entry of the virus. Thus, the binding of SARS-CoV-2 spike protein to the ACE2 receptor is a primary critical step in the entry of the virus into the body and by inhibiting this interaction, it's possible to prevent further viral replication and spread in the body. With all the major virus strains, the differences are in the viral spike proteins which results in distinctive binding of ACE2 receptor.


To evaluate the ability of antiviral preparation to inhibit the binding of spike protein and ACE2 receptor, we have developed a biochemical assay to demonstrate the efficacy of the bovine antibodies in BioBlock. To study the effect on different strains, a development period of several months precedes. “Together with our team, we are constantly monitoring the changes in the virus and proactively testing BioBlock’s ability to neutralize even those strains that are not yet widespread“ said Icosagen Chief Scientific Officer Mart Ustav Jr in a recent interview to Delfi Forte.

Icosagen has analyzed the ability of the antibodies, isolated from bovine colostrum in BioBlock, to inhibit the binding of the viral spike protein and human cellular receptor ACE2. Biochemical analysis and a pseudovirus assay showed that BioBlock was effective in preventing this interaction in all virus strains.


In a biochemical analysis, the SARS-CoV-2 trimeric spike protein was attached to the assay plates and the antibodies used in BioBlock were added. The antiviral antibodies in solution bound to the spike protein at the bottom of the plate. Then, ACE2 receptors were added, which were unable to bind to the viral spike protein now that the previously added antibodies block it. The amount of binding between the ACE2 receptor and the viral spike protein is measurable, and the lower the binding, the better the added antibodies block the entry of the virus.

Our results so far show that the BioBlock solution blocks the interaction between the spike protein and ACE2 receptor from five different virus strains in a concentration dependent manner, thus blocking the virus from entering the host cells. 

To further characterize the virus neutralizing potency of the antibodies in the BioBlock solution, the pseudoviral neutralization assay was performed. In a pseudoviral neutralization assay, the ability of viral particle to bind ACE2 receptor and entry to cells, is directly measured. Compared to a biochemical analysis, this assay is even more similar to an actual viral infection as it allows to measure the efficacy of spike protein-dependent infection and inhibition of viral entry into the cell occurs as decreased enzymatic activity. It is important to note that this effect was entirely based on specific antiviral antibodies produced by immunization, as colostrum antibodies from non-immunized cows showed no effect.

BioBlock®, a natural nasal spray containing bovine antibodies against SARS-CoV-2, developed in collaboration with a consortium of Estonian researchers and entrepreneurs, is on sale in well-stocked pharmacies, Coop stores, Alexela gas stations, as well as in Tallink and Medihex online shops.

For companies, wishing to purchase BioBlock® nasal spray for their employees, please contact:, phone: +372  5857 7040.

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