Researchers from the Karolinska Institute in Stockholm, Sweden, have found that nasal drops containing secretory antibodies, known as "immunoglobulins" (IgA), may protect against infection with "SARS-CoV-2".

A New Anti-Infective Method
The results point to a new method of protecting individuals at high risk of various types of viruses, and possibly other infections, including the flu and other respiratory infections.

The study was published in the Proceedings of the National Academy of Sciences (PNAS) on January 9, 2024, by a team led by Professor Qiang Pan Hammarström at the Karolinska Institute for Genetic Engineering. The study aimed to create a type of "immunoglobulin" antibodies that bind to the viral protein in a similar manner to natural immunoglobulin antibodies.

"Immunoglobulin"
Immunoglobulin is a type of antibody that defends against harmful microbes and forms the immune response. It is the predominant antibody in the intestines, respiratory mucosa, breast milk, and other secreted fluids. It is produced by B lymphocytes and then transferred to fluids secreted by mucosal cells. Naturally present in the mucous membranes of the airways, it is part of the adaptive immune system. Low levels of "IgA" in the mucosal membrane are associated with an increased risk of invasive "SARS-CoV-2" infection.

Traditional "COVID-19" vaccines primarily trigger an "IgG" antibody response, but their efficacy against new "Omicron" variants is limited. To address this issue, researchers have designed "IgA" antibodies that bind to the viral protein in a manner similar to natural (IgG) antibodies, indicating a potential new approach to protect individuals at severe risk from various types of viruses and infections.

Neutralizing the Virus
The researchers observed that mice infected with the "Omicron" variant and treated with (IgA) antibodies through a nasal spray had significantly reduced viral loads in the trachea and lungs. They also noticed that "IgA" antibodies bind more strongly to the virus's spike protein and were more effective in neutralizing the virus compared to original (IgG) antibodies.

The results suggest that genetically modified antibodies could enhance protection against new viral variants, but they are not intended to replace current vaccines.

While traditional vaccines provoke an active immune response from the body, this strategy is a form of passive immunization. The study indicates that this approach might not be suitable to protect the most vulnerable individuals, such as the elderly or people with weakened immune systems, as stated by Harold Marcotte, an associate professor in the Department of Medical Biochemistry and Biophysics at the Karolinska Institute and the study's lead researcher.

Other Respiratory Infections
There are also hopes of using this method to neutralize other current and emerging variants of the virus, and this could be a highly promising strategy not only for "COVID-19" and new variants but also for other infectious diseases, including influenza and other respiratory infections for which there is currently no available vaccine, says Qiang Pan Hammarström, professor in the same department and the paper's last author. He added that it could be beneficial even in reducing mucosal infections in the stomach like those caused by "Helicobacter pylori" bacteria.

The results suggest that this passive immunization strategy is not intended to replace current vaccines that stimulate the body's active immune response.

On the other hand, the "Daily Express" website reported on January 7, 2024, that scientists are discussing the use of a nasal spray containing "Ethyl Lauroyl Arginate Hydrochloride" (ELAH) to prevent viruses from adhering to the nasal passages. The spray has been proven to be safe and effective in helping to prevent infections caused by the "rotavirus" leading to diarrhea, the respiratory syncytial virus that causes common colds and influenza, and coronaviruses, including "COVID-19".