How Does Moderna’s mRNA Vaccine Measure Up to Pfizer’s?

Moderna is out with interim results for its coronavirus vaccines, saying that it is 94.5% effective in preventing COVID-19, a bit more efficacious than Pfizer’s mRNA-based vaccine. However, one must consider that the data is preliminary, and a lot remains to be determined about the workings of the vaccine. Let’s have a look at the vaccine data from Moderna’s Phase 3 COVE Study and how it compares with Pfizer’s vaccine.

What did Moderna Find Out?

In July, Moderna launched the Phase 3 trial of its mRNA-based coronavirus vaccine, where 30000 participants were enrolled. Half of them received two doses of vaccine, and the other half received two doses of placebo. While the participants were being vaccinated, the company waited for them to get naturally infected to determine if the vaccine offered any protection against the virus. So far, 95 participants have got infected, in which 90 cases of the infection-including 11 severe cases were observed in the placebo group and five in the group that received the two-dose vaccine. That resulted in an estimated vaccine efficacy of 94.5%.

Meanwhile, Pfizer reported a vaccine efficacy of 90% in a study that included 94 infected participants. It may seem 94.5% is better than 90% efficacy. However, both are considered very good when one looks at vaccines’ efficacies made for other infectious agents. Again, one must remember that preliminary data and numbers will change when the final data arrives.

How is the Interim Analysis Conducted?

The interim analysis counted the number of participants who contracted the virus following two shots of placebo or vaccine. However, when the counting began, those who were considered positive differed for Moderna and Pfizer’s trials. Moderna’s interim analyses counted participants 14 days following the second injection, whereas Pfizer started counting after seven days of the second injection. To be considered as COVID positive, Moderna required the participant to have at least two symptoms of disease in addition to a positive test for the virus. The Pfizer study required only one symptom.

Is it Safe for Public Use?

So far, the company has reported no “significant” side effects for their vaccine. The vaccine was generally well tolerated, with the majority of adverse events in participants being labeled as mild or moderate. The only side effects observed included pain at the injection site and after the second dose, fatigue, muscle pain, and headaches. The safety data is consistent with the Phase 1 trial of the vaccine.

Even Pfizer reported similar side effects for its vaccine, which included fever and fatigue-neither of which are serious. In terms of safety, both the vaccines are good for public use.

Can Moderna’s Vaccine Reach People Worldwide?

Moderna says that its vaccine can be safely stored in freezers with a temperature of -4°C for up to six months. This means that the vaccine can be easily stored in refrigerators found in homes and hospitals. On the other hand, Pfizer‘s vaccine requires specialized ultracold freezers capable of cooling below -70°C. Such refrigerators are not generally found in clinics or hospitals and can make it difficult for Pfizer to distribute its vaccine. Moderna also says that its vaccine will remain potent at normal refrigerated temperatures of 2° to 8°C for up to 30 days. This will make it easy for the company to distribute its vaccine worldwide.

Does the Vaccine Work Well in Older Populations?

Out of 95 COVID-19 cases, 20 participants in the Moderna vaccine trial were from diverse communities, including 12 Hispanic, four African Americans, three Asian Americans, and one multiracial. Fifteen of them belonged to the age group above 65. However, it remains to determine how many older people received the vaccine and were protected from the infection.

Pfizer, on the other hand, did not reveal any information about the ethnicity or the age of these people. However, their trial includes people over the age of 65, so it will eventually provide crucial information.

When will the Vaccine Come Out?

Based on the interim data, Moderna is planning to submit an Emergency Use Authorization (EUA) with the USFDA in the coming weeks. But EUA authorization will be determined after the company has submitted efficacy and safety analysis from 151 COVID-19 cases monitored for more than 2 months.

It expects to have 20 million doses available in the country. The company plans to manufacture 500 million to 1 billion doses globally in 2021. However, for global distribution, it will need authorization from global regulatory agencies. Moderna will soon start filling with the global agencies to get their approval at the earliest. The company has supply agreements in North America, the Middle East, and other regions of the world. Pfizer will apply for emergency authorization in the third week of November after collecting the two months of safety data that the FDA asked the manufacturers to submit.

Once the data is submitted to the advisory committee of experts, it will take weeks for the experts to go over the data about the vaccines’ safety and effectiveness. The vaccines could be authorized for the high-risk population before the year-end if all goes well.

By Ruchi Jhonsa, Ph.D.

Related Article: Moderna’s Shares Surge Following Claims of 94.5% Efficacy for its COVID-19 Vaccine

References

1. https://investors.modernatx.com/news-releases/news-release-details/modernas-covid-19-vaccine-candidate-meets-its-primary-efficacy
2. https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-longer-shelf-life-its-covid-19-vaccine
3. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-vaccine-candidate-against

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Ruchi Jhonsa