Oral Vaccines: A New Drug Development Area that Must be Paid Attention to under the COVID-19 Epidemic

Chinese researchers have recently reported the development of an oral formulation for preventing and treating the COVID-19. The report was controversial as it was initially reported as the successful development of the "oral vaccine". The news title of each related platform might be different, however, readers who could read carefully the report contents would discover that it is indeed some progress in the COVID-19 "oral vaccine" development, but only that it has not been conducted the clinical study and is far from being marketed. Seen from the controversies on each exchange platform, it seems that the oral vaccines are a very strange area to people and worth talking about systematically.

From the perspective of the mechanism of action, oral vaccines mainly act on the mucosal immune system. We know that mucosal immunity is the first line of defense against most pathogen infections. And mucosal infection is one of the main routes of infection as seen from the novel coronavirus spreading. Therefore, the "oral vaccines" that can produce mucosal immunity must be an effective way to control the novel coronavirus and also hepatitis C, hepatitis B, human papilloma virus, and influenza virus, etc.

For example, the authoritative journal The Lancet has recently reported the Phase II clinical study results of the oral influenza (H1N1) vaccine: VXA-A1.1 of Vaxart, Inc.: safe and effective!

Besides the influenza vaccine, the approved "oral vaccines" mainly include 5 types, including the antiviral vaccines: rotavirus vaccine and polio vaccine; and antibacterial oral vaccines: Helicobacter pylori vaccine, cholera vaccine, and typhoid vaccine. If you are looking for wholesale medical supply companies offering vaccines, Pharmasources would be your best choice.

A. Rotavirus oral vaccine

As the first approved oral virus against rotavirus, Rotashield was a tetravalent live-attenuated vaccine with significant effects in preventing diarrhea and rotavirus infection, however, it was removed from the market due to the intussusception or ileus risk. Two new oral rotavirus vaccines have been successively approved to replace Rotashield: one is RotaTeq approved in 2006, and the other one is Rotarix approved in 2008.

The related vaccine mainly used in China is the monovalent lamb RV (LLR): Rotavirus (Live) Vaccine, Oral independently developed and produced by Lanzhou Institute of Biological Products Co., Ltd. LLR has good immunogenicity and can induce vaccinated people to produce G1-G4 neutralizing antibodies. The vaccine has been used for tens of millions of doses (person-times).

B. Polio oral vaccine

The polio oral vaccine was developed early. Oral polio vaccine (OPV) developed by Albert Sabin was the first mucosal vaccine approved. According to the research, this oral vaccine could produce protective immune responses similar to that of the inactivated polio vaccine (IPV) developed by Jonas Salk. Since the use of OPV, polio incidence has rapidly declined in many countries. The use of this vaccine is discontinued in some countries, however, it indeed has made great contributions to humans’ fight against polio!

C. Antibacterial oral vaccines

Oral recombinant Helicobacter pylori vaccines are genetically engineered vaccines produced by recombining Helicobacter pylori urease B subunit (UreB) and the heat-labile enterotoxin B subunit (LTB) of the mucosal immune adjuvant enterotoxigenic Escherichia coli (ETEC). China’s pharmaceutical R&D entered the area early. The State Food and Drug Administration of China (currently, the NMPA) approved the new drug certificate and pharmaceutical product registration approval of the related oral vaccine early in 2009. And the world’s first vaccine against Helicobacter pylori infection was also from China.

Besides Helicobacter pylori oral vaccines, antibacterial oral vaccines including cholera vaccines (such as CVD103HgR and Bengal 15) and typhoid vaccines (such as CVD 908-htrA and Ty800), etc. have also achieved great progress.

It can be seen from the above that oral vaccines have made great contributions to humans’ resistance to viral and bacterial infections, etc. There will be more excellent oral vaccines produced in the future as the R&D technologies mature and improve. It’s hoped that the related vaccine of the COVID-19 could be accelerated R&D and produced soon to contribute to the fight against the COVID-19.

References:

1. Efficacy, immunogenicity, and safety of an oral influenza vaccine: a placebo-controlled and active-controlled phase 2 human challenge study, 2020;
2. Antirotavirus IgA seroconversion rates in children who receive concomitant oral poliovirus vaccine: A secondary, pooled analysis of Phase II and III trial data from 33 countries, 2020;
3. The First Clinical Use of a Recombinant Lactococcus lactis Expressing Human Papillomavirus Type 16 E7 Oncogene Oral Vaccine: A Phase I Safety and Immunogenicity Trial in Healthy Women Volunteers, 2020.

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