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Experimental mRNA flu vaccine shows promising results

The biotech company Moderna, which created a highly efficient mRNA vaccine against SARS-CoV-2 last year, has recently announced that their new flu vaccine appeared to be safe and efficient after Phase 1 trials.

“Even before the COVID-19 pandemic, approximately three million people died each year due to respiratory infections, and many more are hospitalized or become ill as a result of these viruses,” said Stéphane Bancel, the Chief Executive Officer of Moderna. 

Thus, influenza vaccination can be a powerful weapon against a class of dangerous pathogens. The current anti-flu vaccines are based on inactivated viruses cultivated in chicken eggs, and usually have an efficacy ranging from 40 to 60 percent. The manufacturing process is quite long, since virus strains need to be selected six to nine months before the development and intended use of the vaccines.

By contrast, the new mRNA technology, which provokes an immune response by delivering to human cells genetic molecules that contain the code for key parts of a pathogen, can significantly accelerate immunization development and production and heighten vaccine efficacy. 

Moreover, several mRNA molecules encoding for different viral strains can be delivered in the same shot. Moderna’s experimental flu shot is “quadrivalent,” targeting four strains of flu (A/H1N1, A/H3N2, B/Yamagata and B/Victoria). In the future, Moderna aims to develop a “pan-respiratory booster,” targeting not only the circulating flu strains, but also SARS-CoV-2 variants, and the respiratory syncytial virus (RSV).

The current anti-flu vaccine was tested on 180 people of different ages, at various dosage levels, and found to be safe and efficient. “The positive interim results from our Phase 1 quadrivalent flu vaccine candidate, mRNA-1010, are an important milestone,” said Bancel. 

“It is encouraging to see that participants in the study who received the 50 µg dose, including older adults, achieved robust increases in geometric mean antibody titers against H1N1 and H3N2, the strains responsible for the vast majority of morbidity and mortality in this age group We believe our mRNA platform is well-positioned to address the significant unmet need in seasonal flu as evidenced by our new beyond quadrivalent candidates, mRNA-1011 and mRNA-1012, which we believe will expand strain coverage and provide more options for public health officials.” 

The side effects of the vaccines appeared mild, and occurred more often in younger rather than older adults. The most common ones included pain at the injection site, headaches, muscle and joint aches, and tiredness. 

The results of the second stage of the trials, involving 500 participants, are expected in the first part of 2022. 

By Andrei Ionescu, Staff Writer

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