Scientists Work On an Oral Vaccine Booster for COVID-19

Every time a new coronavirus variant surfaces, vaccine manufacturers and countries will ponder over whether a variant-specific booster needs to be manufactured and administered to large parts of the population. Even as richer countries manage to secure their doses early on, the real challenge of containing the pandemic is vaccinating the world at large. Now, a Hong Kong-based biotech company, DreamTec, could potentially alter the course of the pandemic with its orally administered vaccine that can be stored at room temperature. 

Shiny New Toys

In a recent interview, Dr. Peter Hotez, the Dean of Houston-based Baylor College of Medicine’s Tropical Medicines School and Chair at Texas Children’s Hospital referred to mRNA-based vaccines as ‘shiny new toys’ that had little effect on global health. Hotez referred to conventionally used vaccine platforms such as virions, pathogen fragments, and even recombinant DNA technology that can be used to grow proteins of interest in yeast cells as potential methods of vaccinating the world.

DreamTec’s approach also uses recombinant DNA technology but takes it a step further by making a vaccine that does not need to be injected, making it extremely easy to administer. The company achieved this by inserting the SARS-CoV-2 spike protein receptor-binding domain (sRBD) into Bacillus subtilis spores. 

A Trusted Ally

B.substilis is a Gram-positive rod-shaped bacteria that is commonly seen in the gastrointestinal tract. Its spores are known to be tolerant to extreme environmental conditions, including the heat during cooking and the acidity of the human stomach. The bacteria have also been extensively studied as a model organism in microbial labs and also found utility as an enzyme producer by the food manufacturing industry.

The U.S. Food and Drug Administration (US FDA) categorizes B.subtilis and products derived from it under Generally Regarded As Safe (GRAS) while the Japanese Ministry of Health has recognized the organism as the principal component of Natto, fermented soybean that has been associated with healthy gut flora and vitamin K2 intake. 

The recombinant B.subtilis spores activate in the small intestine and generate a mucosal-specific immune response without entering the bloodstream, the press release said. Since the technique uses recombinant technology, if required, even a variant-specific vaccine could be made in months. 

The vaccine or its booster consists of billions of recombinant spores packed in a capsule that needs to be ingested as part of an inoculation drive. These capsules can be stored at room temperature and transported across the globe. 

The researchers are still in the early phases of their work but also completed a pilot study consisting of nine participants, which concluded in November last year. Peer-reviewed results from the study are available in a paper published in the journal Vaccines. 

Earlier we had reported that Canadian firm Medicago was in the final stages of its Phase 3 trial for a COVID-19 vaccine made in plants. 

Author

Ameya Paleja