Explained: What is the Moderna mRNA-1273 vaccine?

India will soon get its fourth Covid-19 vaccine after Covishield, Covaxin and Sputnik V. On June 29, US-based biotechnology major Moderna was granted emergency use authorisation (EUA) for its vaccine based on mRNA technology. According to NITI Aayog member (health) VK Paul, the regulatory clearance potentially opens up a clear possibility of the vaccine being imported into the country in the near future. He added that the government is also making efforts to bring in other internationally developed vaccines, specifically Pfizer and Johnson & Johnson.Indian pharma major Cipla will “facilitate” the import of the Moderna vaccine. “This is not a commercial or supply deal, and we do not distribute this consignment either,” said Cipla’s global CEO Umang Vohra. However, Cipla is reportedly also pursuing a separate tie-up with the US firm to undertake large-scale fill-and-finish, distribution and commercialisation of this vaccine.Here’s all you need to know about this incoming addition to India’s vaccine arsenal:What do we know about the Moderna vaccine?The Moderna vaccine is a messenger ribonucleic acid (mRNA) vaccine. This will be the first such vaccine in India. Such nucleic acid vaccines use genetic material from a disease-causing virus or a pathogen to stimulate an immune response against it. “By hijacking the cellular mechanisms, such vaccines mimic the way viruses normally reproduce during natural infections. But instead of creating copies of the virus, the cells only produce large amounts of antigen,” says GAVI-The Vaccine Alliance.Formally called mRNA-1273, the vaccine received emergency use authorisation (EUA) from the US Food and Drug Administration (FDA) in December 2020. It was the second vaccine to get the green light after the Pfizer-BioNTech vaccine, which is also mRNA-based.The Moderna vaccine has also been granted permission for restricted use in over 50 countries and an Emergency Use Listing (EUL) from the World Health Organization (WHO). Moderna has also filed for EUA for use of its Covid-19 vaccine for adolescents with health agencies in the European Union, Canada, the US, Switzerland and Japan. medium83995814How does this vaccine work?The SARS-CoV-2 virus, which causes Covid-19, uses proteins on its outer surface, called spike proteins, to enter the body’s cells. The Moderna vaccine (like other mRNA vaccines) encodes instructions for making this spike protein into an instruction molecule called mRNA. Instead of introducing antigens into the body — a weakened or inactivated germ in the case of Covid-19 vaccines — mRNA vaccines teach our cells how to produce the protein. Once the vaccine is injected, the mRNA is taken to immune cells, where it instructs cells to make copies of the spike protein. But this does not cause disease. It instead triggers the immune system to learn to react defensively, producing an immune response should the vaccinated person ever come in contact with SARS-CoV-2 in the future.A recent study published in Nature journal suggests that the immune response to mRNA vaccines may be so long-lasting that it may make booster shots unnecessary. To remind you, in April, Moderna and Pfizer had both claimed six months of immunity with their respective vaccines.The Centers for Disease Control and Prevention makes it clear that the mRNA vaccines do not use the live virus that causes Covid-19. “mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions,” a CDC release says.A possible complication, as and when the Moderna vaccine reaches Indian shores, is that it needs to be kept in ultra-cold freezers. The multiple-dose vials need to be stored at between -50ºC and -15ºC, but not on dry ice. If transporting it in such temperatures is not feasible, available data supports transportation of thawed vials for up to 12 hours at 2° to 8°C with shaking and vibration minimised. But such vials cannot be refrozen and have to be stored at the same temperature and used within 30 days. How effective is the Moderna mRNA-1273 vaccine?“The mRNA-1273 vaccine showed 94.1% efficacy in preventing Covid-19 illness, including severe disease,” read a February 2021 research report on the efficacy and safety of the Moderna vaccine. That makes it more efficacious than the other three vaccines — Covishield, Covaxin and Sputnik V— currently available in India. The study published in The New England Journal of Medicine found frequent but moderate and transient reactogenicity after vaccination. Aside from temporary, local and systemic reactions, no safety concerns were identified. medium83996051Significantly, recent studies indicate that the Moderna vaccine works against the newly detected variants, ranging from Alpha (B.1.1.7) to Eta (B.1.525), but with a modest decrease in response compared to the original strain. This new data was submitted to the open access preprint repository bioRxiv, and is awaiting peer review. According to Moderna, the new data — based on in vitro neutralisation studies of serum samples from eight participants one week after they received the second dose — showed that vaccine-elicited neutralising antibodies reduced two to eight-fold, depending on the variant in question. For instance, the vaccine showed a modest 2.1 fold reduction in producing antibodies against the Delta (B.1.617.2) variant, which is fast becoming the dominant strain worldwide, and a 3.3-3.4-fold reduction against Kappa, the other variant first found in India. “A 7.3 or 8.4-fold reduction in neutralising titers was observed with the additional versions of the Beta variant relative to the ancestral strain,” Moderna said in a recent press release.Does this vaccine have any side effects?The most commonly reported side effects, which typically last several days, are pain at the injection site, tiredness, headache, muscle pain, chills, joint pain, swollen lymph nodes in the arm that gets the jab, nausea and vomiting, and fever. According to the FDA, more people experienced these side effects after the second dose compared to the first shot.Significantly, the federal agency revised its patient and provider fact sheets recently following early research suggesting increased risks of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the tissue surrounding the heart) following mRNA vaccine jabs. “There were no other notable patterns or imbalances by age, race, ethnicity, or medical comorbidities, for specific categories of serious adverse events that would suggest a causal relationship to Moderna Covid-19 vaccine,” it adds.medium84015770What is the recommended dosage?The Strategic Advisory Group of Experts on Immunisation (SAGE) recommends the use of the Moderna mRNA-1273 vaccine at a schedule of two doses 28 days apart. If necessary, the interval between the doses may be extended to 42 days. According to WHO, studies have shown a high public health impact where the interval has been longer than that recommended by the EUL. Can the Moderna and Pfizer vaccines be interchanged?“There is no data available on the interchangeability of Moderna Covid-19 Vaccine with other Covid-19 vaccines, including Pfizer-BioNTech Covid-19 Vaccine,” says FDA. So if you opt for a first dose of the Moderna mRNA-1273 vaccine, you should take the follow up dose instead of switching to another vaccine to complete the vaccination series.Is this vaccine dangerous?The WHO advises that individuals with a history of severe allergic reaction to any component of the vaccine should not take this or any other mRNA vaccine. Sources: Moderna, World Health Organization, US FDA, European Medicines Agency, Reuters, GAVI - The Vaccine Alliance, Centers for Disease Control and Prevention