Faster vaccines likely if Moderna effort succeeds
Moderna’s experimental vaccine against the coronavirus disease (Covid-19) has emerged the front-runner in the global effort to stop the pandemic after an early trial showed it produced virus-neutralising antibodies similar to those found in recovered patients.
It is one of at least 20 experimental nucleic acid vaccines against Covoid-19 in various stages of clinical development that use the messenger RNA (mRNA) platform to elicit an immune response against SARS-CoV-2, the virus that causes Covid-19, according to the World Health Organization (WHO)’s draft landscape of Covid-19 candidate vaccines. Most of these vaccines encode the spike protein of Sars-CoV2.
“If it is approved, it will be the first messenger RNA (mRNA) vaccine against any disease in the world. We don’t fully know the effectiveness of mRNA vaccines as yet. However, there is high quality science and pre-clinical evidence for this fast and flexible platform for vaccine development. We will have to wait and see,” said Dr Anurag Agrawal, Council of Scientific and Industrial Research-Institute of Genomics & Integrative Biology, New Delhi.
The new vaccine, called mRNA-1273, encodes for a pre-fusion stabilised form of the spike (S) protein selected by Moderna in collaboration with the US Vaccine Research Center at the National Institute of Allergy and Infectious Diseases. mRNA vaccines are promising alternatives to conventional vaccine approaches because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration.
“This is great news as RNA- and DNA-based vaccines are faster and cheaper to produce than synthetic vaccines as it involves synthetic production of the genetic material, and not the virus. The production is lab-based, so it can be quickly standardised and scaled up,” said Dr N K Ganguly, former director general, Indian Council of Medical Research.
Vaccines work by training the body to recognise and respond to the proteins produced by disease-causing organisms, such as a virus or bacteria. Traditional vaccines use small or inactivated doses of the pathogen (virus or bacterium), or the proteins it produces, to provoke an immune response after vaccination without causing disease.
mRNA vaccines use a synthetic version of the genetic blueprint the virus uses to build its infectious proteins. The synthetic nucleic acid is inserted into human cells, the humans cells read it as instructions to build fragments of the viral protein, which the immune system attacks by building antibodies against them.
“Technological advances have made in vivo delivery of mRNA efficient, and several mRNA vaccine platforms against infectious diseases and some cancers have demonstrated encouraging results, in both animal models and humans,” said Ganguly.
This makes mRNA vaccines safer for patients as they don’t contain infectious material. Some experimental mRNA vaccines against certain cancers and allergies are in early stage clinical trials, but none have been approved for use.
“For its messenger RNA vaccine, Moderna uses lipid-polymer hybrid nanoparticles (LPNs), which are known messengers with established safety. In India, Gennova Pharmaceuticals has also developing an mRNA vaccine, which it will use with its patented carrier lipid iron oxide (LION) and an adjuvant known as GLA-SE,” said Ganguly.
Gennova Pharmaceuticals has conducted experiments ... and obtained very high neutralizing antibody titres,” said Ganguly. A senior company official declined comment, saying the work was in its early stages.
The US pharma company Pfizer, is working on four nucleic acid vaccines, of which three are mRNA; the other one contains self- amplifying mRNA. Pfizer collaborated with a German company, BNTECH, to identify the most viable candidates and tests are underway in Germany and the US. The DNA vaccine developed by INVIO Pharmaceuticals work is in phase I /II trials at the International Vaccine Institute in South Korea..
There is no approved vaccine for Sars-CoV2, although around 120 vaccine candidates are in various stages of clinical trial. “If mRNA-1273 is successful, it should be ready for commeriail use by January next year,” said Ganguly.
Moderna’s vaccine will be produced by the US government and Swiss contract drugmaker, Lonza Group, which has said it will produce one billion doses a year. “We are investing to scale up manufacturing so we can maximize the number of doses we can produce to help protect as many people as we can from Sars-CoV-2,” Moderna Chief Executive Officer, Stéphane Bancel said in a statement.