Moderna’s Covid-19 vaccine: How many doses will be available in the US? Is it safe? Everything we know so far

The company said it would have 20 million doses ready to ship in the US by the end of 2020 and hoped to manufacture 500 million to 1 billion doses globally in 2021

                            Moderna’s Covid-19 vaccine: How many doses will be available in the US? Is it safe? Everything we know so far
(Getty Images)

There are now two promising coronavirus vaccines on the horizon with Moderna announcing that their experimental vaccine was 94.5% effective in preventing Covid-19. This is according to the first interim analysis of its ongoing Phase 3 clinical trial that included 95 participants with confirmed cases of Covid-19. On November 9, Pfizer and its partner BioNTech announced that the vaccine being developed by them has shown to be over 90% effective at protecting people against coronavirus. 

“This positive interim analysis from our Phase 3 study has given us the first clinical validation that our vaccine can prevent Covid-19 disease, including severe disease,” noted Stéphane Bancel, chief executive officer of Moderna.

Like Pfizer’s announcement last week, this update was provided in a press release, and the actual data still need to be published and reviewed. However, the news is promising that multiple highly efficacious vaccines could be available in 2021, say experts. What do we know so far about the Moderna vaccine?

What did the results reveal?

Based on data from 95 participants with confirmed cases of Covid at least two weeks after the second dose of the vaccine, the researchers report that the vaccine has an efficacy of 94.5%. In other words, 90 of the Covid cases occurred among participants who had been given placebo jabs, with only five cases occurring among those given the vaccine.

“The independent, NIH-appointed Data Safety Monitoring Board (DSMB) for the Phase 3 study of mRNA-1273, its vaccine candidate against Covid-19, has informed Moderna that the trial has met the statistical criteria pre-specified in the study protocol for efficacy, with a vaccine efficacy of 94.5%,” the company announced in a statement on November 16.

Among the 95 cases, 15 were aged 65 years or older and 20 were racial or ethnic minorities — 12 Hispanic or Latino, 4 Black or African American, 3 Asian, and 1 multiracial. Notably, 11 severe Covid-19 cases were reported among trial participants, and all were among the placebo group. 

How does it work?

The Moderna vaccine is administered in two shots, 28 days apart. Similar to Pfizer’s, it is an mRNA-based vaccine candidate. This means that the vaccine is based on genetic material called mRNA, which targets the spike protein that sits on the outside of the SARS-CoV-2 virus that allows the virus to attach to and invade human cells, initiating infection.

The vaccine introduces this mRNA to the human body, triggering human cells to produce the spike protein. In response to these proteins, the body produces antibodies and other immune pathways are activated, guarding against infection. 

The Moderna vaccine, which has an efficacy of 94.5%, is administered in two shots, 28 days apart
(Getty Images)

Was there any adverse reaction?

The vaccine appears to have an acceptable safety profile. The company noted there were no ‘significant’ safety concerns, adding the vaccine was generally safe and well-tolerated, with the majority of adverse events in participants being labeled as mild or moderate. 

“Grade 3 (severe) events greater than or equal to 2% in frequency after the first dose included injection site pain (2.7%), and after the second dose included fatigue (9.7%), myalgia or muscle pain (8.9%), arthralgia or joint pain (5.2%), headache (4.5%), pain (4.1%) and erythema/redness at the injection site (2.0%). These solicited adverse events were generally short-lived. These data are subject to change based on ongoing analysis of further Phase 3 COVE study data and final analysis,” said Moderna.

What about storage?

Moderna’s vaccine can be stored in a standard refrigerator for up to 30 days, which implies that unlike Pfizer’s shot, it will not require a deep freeze. Additionally, the Moderna vaccine can remain at room temperature for up to 12 hours and does not require onsite dilution or additional handling at the vaccination site, which could reduce the logistical burden required for mass vaccination.

The company announced that the vaccine has demonstrated longer shelf life and greater stability at refrigeration temperatures than initially anticipated. Data indicates it “remains stable at 2°C to 8°C (36°F to 46°F)...for 30 days” and “at -20°C (-4°F) for up to six months.” 

Questions remain

A big unknown is how long the immunity provided by the vaccine will last. Researchers also want to know if the vaccine prevents people from spreading the virus.

What happens now?

Moderna intends to submit for an Emergency Use Authorization (EUA) with the US Food and Drug Administration (FDA) in the coming weeks and expects the EUA to be based on the final analysis of 151 cases and a median follow-up of more than 2 months. “As more cases accrue leading up to the final analysis, the company expects the point estimate for vaccine efficacy may change. The company plans to submit data from the full Phase 3 COVE study to a peer-reviewed publication,” it said. Moderna also plans to submit applications for authorizations to global regulatory agencies.

It is not known if the vaccine prevents people from spreading Covid-19 (Getty Images)

When can Americans expect a vaccine?

US officials said they have plans to have enough vaccines available for use from Moderna and Pfizer to immunize about 20 million Americans in December. The most vulnerable populations, including nursing home residents, are expected to get the vaccine first, followed by healthcare workers and first responders.

Americans will get the vaccines for free. In August, Moderna had announced that the US government has secured 100 million doses of its vaccine. The federal government’s Operation Warp Speed awarded Moderna up to $1.525 billion in August for manufacturing and delivering the 100 million vaccine doses. The US government has an option to buy up to an additional 400 million doses. 

By the end of 2020, Moderna expects to have approximately 20 million doses of mRNA-1273 ready to ship in the US. The company also stated that it “remains on track” to manufacture 500 million to 1 billion doses globally in 2021. It is working with the US Centers for Disease Control and Prevention (CDC), Operation Warp Speed, and McKesson vaccine distributor contracted by the US government, as well as global stakeholders to be prepared for the distribution of mRNA-1273, if it receives an EUA and similar global authorizations. 

How many participants have been enrolled so far?

This study, known as the COVE study, was designed in collaboration with the FDA and National Institutes of Health (NIH) to evaluate Americans at risk of severe coronavirus disease. It completed enrollment of 30,000 participants ages 18 and older in the US on October 22, including those at high risk of the severe complications of Covid-19. 

Moderna told investors on October 29 that it was “actively preparing” for the global launch of its potential vaccine after completing enrollment in its phase three trial a week earlier. It said about 37% of the participants were from minority communities and 42% had high-risk chronic conditions or ages (over 65) that put them at high risk of severe disease. 

What are experts saying?

“These are obviously very exciting results. It’s just as good as it gets; 94.5% is truly outstanding,” said Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID). The Moderna study is being conducted in collaboration with the NIAID.

Stating that the results are “highly encouraging,” Dr Charlie Weller, head of vaccines at Wellcome, cautioned that as with other studies, “we must remember they are interim and we are yet to see the full data.” “Urgent questions remain to be answered, including how long these vaccines will be effective for and whether these vaccines work across different populations, in all age groups, ethnicities, and those with prior health conditions. Only upon trial completion will we be able to assess the full efficacy and safety of any vaccine candidate,” he added. 

Dr Penny Ward, visiting professor in pharmaceutical medicine at King’s College London explained that it is important to know if there is protection against infection. “While protection against illness has a value for an individual, it will not prevent the circulation of virus and risk of disease in unvaccinated persons, or in people not responding adequately to vaccination,” he stated. 

Eleanor Riley, professor of immunology and infectious disease at the University of Edinburgh agrees. “One important unknown is whether this vaccine or any of the vaccines currently in trials, prevents disease transmission,” she said. However, stating that Moderna results are broadly similar to the Pfizer/BioNtech data, and having more than one source of an effective vaccine will increase the global supply and, “with luck, help us all to get back to something like normal sometime in 2021.” “Each of these trials is still in the early phases of reporting and as more cases accrue the efficacy estimates may change slightly, but the fact that two independent trials are giving very similar results is very reassuring,” she added. 

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