In its review, the panel confirmed Moderna’s earlier assessment that its vaccine had an overall efficacy rate of 94.1%. Side effects — including fever, headache and fatigue — were common, but the experts said they had identified no specific safety concerns. The US-developed vaccine was found to be only 86% effective in people over 65, lower than the almost 94% reported by Pfizer-BioNTech.

Although the experts said the benefits of the vaccine outweigh the risks for people 18 and older – just as for the Pfizer-BioNTech candidate, which is also mRNA-based – they also warned of the possibility of a partial facial paralysis called Bell’s Palsy that had cropped up during trials. The FDA is investigating the incidence of the condition, which it said was not necessarily related to the vaccine.

The analysis did not find serious allergic reactions to the Moderna vaccine based on trial data. Although such reactions were also not seen in the Pfizer-BioNTech trials, two health care workers in the UK with a history of serious allergies developed severe anaphylaxis. A healthcare worker in the US state of Alaska with no previous history of allergies reportedly suffered flushing and shortness of breath 10 minutes after receiving the German-American vaccine.

Questions that came up during the FDA panel’s review of Moderna’s candidate concerned what would happen to the company’s ongoing Phase 3 clinical trial with 30,000 patients if the vaccine was already being administered to others. Some of the panelists argued that it would be unethical to continue giving the placebo.

The US Centers for Disease Control and Prevention (CDC) meanwhile has given the green light to immediately begin vaccinating people aged 18 and older with the Moderna vaccine. The CDC said earlier that people with serious allergies could be safely vaccinated if closely monitored for 30 minutes afterward. Following criticism of the age bracket 16 and up agreed for the Pfizer-BioNTech shot, the CDC raised the lower age bracket to 18.

Despite unexplained delivery delays for the Pfizer-BioNTech vaccine, "we still anticipate that every American will have the opportunity to be vaccinated by June," Brett Giroir, assistant secretary for health at the US government’s Department for Health and Human Services (HHS), said last week. Large groups of Americans nevertheless remain hesitant about receiving the shot, with the Black population said to account for around a third of the skeptics.

The US government has purchased altogether 300 million doses of the Moderna candidate, enough to vaccinate 150 million people under a two-dose regime.  It also has an option on 200 million more. The vaccine is being provided free of charge, as it received substantial federal development aid.

In spite of the emergency approval of a second vaccine, a study model published by the University of Washington on Dec. 18 projected that 562,000 people in the US will have died from Covid-19 by Apr. 1, substantially more than the 502,000 deaths forecast a week earlier.

Supply deals with countries worldwide

Beyond the US, Moderna has also sealed supply agreements with a number of other countries or blocs. The EU has signed up for 160 million doses, Japan for 50 million and Canada for 40 million, with an option for an additional 16 million. Switzerland has agreed to buy 7.5 million doses, the UK 7 million and Israel 6 million.

The US vaccine maker plans to begin deliveries to Europe in early 2021, providing the European Medicines Agency (EMA) grants authorization. A meeting to review efficacy and safety data has been moved up from Dec. 29 to Dec. 21.

Unofficial reports published during the negotiations put the negotiated price for the Pfizer-BioNTech vaccine at €12 per dose and the price for Moderna's at $18 per dose.

Author: Dede Williams, Freelance Journalist