Creators of a new protein-based coronavirus vaccine say it is 100% effective at preventing severe illness and hospitalization.
Sanofi and GlaxoSmithKline (GSK) are seeking EU and US regulatory approval of their protein-based COVID-19 vaccine, which proved 100% effective at preventing severe illness in phase three clinical trials, the duo announced on Wednesday.
The two pharmaceutical companies have been working in tandem, funded by the US government, to develop a vaccine since the start of the pandemic. Sanofi is headquartered in France and GSK in Britain.
Initially expected to create the world's very first vaccine through the standard protein-based approach, which is used in vaccines against Hepatitis B and pertussis, the companies didn't deliver after lackluster clinical trials in December 2020.
One year later, the creators say their vaccine is ready for approval and global distribution.
Official trial results are yet to be published, but the companies reported that in phase three testing, two doses of the vaccine showed 100% protection against severe illness or hospitalization, plus 75% efficacy against moderate illness and 58% efficacy against any symptomatic illness.
To compare, mRNA vaccine giants BioNTech-Pfizer and Moderna announced efficacy rates of around 95% protection against severe illness or hospitalization when results from their phase three clinical trials were released in November 2020. Neither company published efficacy rates against moderate or mild illness, which has since been criticized by some public health experts who say it created unrealistic expectations for the vaccine.
Efficacy rates among all vaccines have lessened against mild symptomatic illness since the outbreak of variants such as delta and omicron. According to one study published in the British Medical Journalin January 2021, mRNA vaccine effectiveness against mild to moderate COVID infection significantly decreased from 82% at 3-4 weeks after the second dose of vaccine to 33% at 27-30 weeks after the second dose.
Protection against severe illness also decreased, albeit not as dramatically, from 96% to 80%.
Sanofi and GSK said an efficacy of 58% against infection is "in line with expected vaccine effectiveness in today's environment dominated by variants of concern."
More than 10,000 people across the US, Asia, Africa and Latin America took part in the Sanofi-GSK trial — significantly fewer than the 43,600 and 30,000 who took part in BioNTech-Pfizer's and Moderna's phase three trials respectively.
The Sanofi-GSK vaccine is primarily being marketed as a booster dose, according to their statement. In participants who had already received two doses of an mRNA vaccine, it increased neutralizing antibodies 18- to 30-fold across age groups, the researchers said.
If approved, the vaccine could be life-changing for people living in low-income countries. The transportation of protein-based vaccines doesn't require the sophisticated cooling methods demanded by mRNA vaccines, making them easier to ship around the world to places with a low supply of COVID vaccines.
Germany started distributing its protein-based Novavax vaccine this week. Although it has been approved for distribution in the EU, it is still awaiting the greenlight from the US Food and Drug Administration.
Edited by: Charli Shield