How Moderna’s coronavirus vaccine differs from Pfizer’s


But there are a few key differences. Most importantly, Moderna’s vaccine can be stored in normal freezers and does not require an ultra-cold transport network, making it more accessible for small facilities and local communities.

While Pfizer is a pharmaceutical giant, Moderna – short for modified RNA – is a biotechnology company based in Cambridge, Massachusetts.
Founded in 2010, Moderna has never brought a product to market or obtained FDA approval for any of its nine vaccine candidates. He had also never brought a product to phase three of a clinical trial before.

Company scientists had previously collaborated with researchers at the National Institutes of Health on a vaccine against another coronavirus, Middle East Respiratory Syndrome (MERS). When Chinese researchers released the genomic sequence for the new coronavirus in mid-January, they got off to a good start.

The vaccine, called mRNA-1273, received development assistance from the National Institute of Allergy and Infectious Diseases. The US Biomedical Advance Research and Development Authority, known as BARDA, has supported advanced clinical trials and helped scale up manufacturing.

Moderna’s vaccine clinical trials get the green light from the FDA on March 3, the first to come out. Its late-stage clinical trial began on July 27, and it was the first government-funded Phase 3 clinical trial for a Covid-19 vaccine in the United States. The company applied to the FDA for emergency use clearance for the vaccine on November 30.

Does the vaccine work?

The Moderna vaccine has been shown to be effective in preventing cases of Covid-19 in total and in limiting severe cases of Covid-19 during the trial.

The vaccine’s effectiveness against Covid-19 was 94.1%, occurring at least 14 days after the second dose, according to a backgrounder released by an advisory committee to the FDA.

In the Moderna trial, 15,000 study participants were given a placebo, which is an injection of saline solution with no effect. Over several months, 185 of them developed Covid-19, with 30 developing severe forms of the disease. One of them died.

Another 15,000 participants received the vaccine, and only 11 of them developed Covid-19. None of the 11 became seriously ill.

The vaccine was effective for all age groups, genders, racial and ethnic groups and participants with medical co-morbidities associated with a high risk of severe Covid-19, according to the backgrounder. About 10% of the study participants were black and 20% were Hispanic or Latin American.

How it works?

Like Pfizer’s vaccine, Moderna provides messenger RNA, or mRNA, which is a genetic recipe for making a piece of the spikes that sit on top of the coronavirus. Once injected, the body’s immune system makes antibodies against the spikes. If a vaccinated person is later exposed to the coronavirus, these antibodies must be ready to attack the virus.

The Moderna vaccine contains in particular a synthetic mRNA which codes for a structure called the virus’ stabilized peak glycoprotein before fusion.

The vaccine also contains fats called lipids, tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate and sucrose.

How is Moderna vaccine different from Pfizer vaccine?

The two vaccines are very similar, but they have a few key differences that make Moderna’s vaccine “more flexible,” as US Secretary of Health and Human Services Alex Azar said last month.

Efficiency: Moderna and Pfizer-BioNTech vaccines have shown similar efficacy levels of nearly 95%.

“They appear to be roughly equivalent,” said Dr. Paul Offit, a member of the FDA’s Vaccine Advisory Board, in an appearance Tuesday on CNN’s “New Day”.

Structure: The two vaccines rely on mRNA, or messenger RNA, to function, although with slightly different structures and composition.

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“Even though they are both messenger RNA vaccines, they are really different messenger RNA molecules, they have different so-called lipid delivery systems, that is, the type of fat droplets. in which messenger RNA is found, ”Offit said Monday. “That’s why they have different storage and handling characteristics. ”

Cold room: More importantly, Moderna’s vaccine does not need to be stored in extremely cold temperatures, like that of Pfizer.

The Pfizer vaccine should be stored at about minus 75 degrees Celsius, about 50 degrees cooler than any other vaccine currently in use in the United States. The vaccine can only be stored in the refrigerator for up to five days before it expires.

To address this, the CDC created a complex set of handling and storage requirements known as the “cold chain” that included expensive ultra-cold freezers and lots of dry ice.

In contrast, Moderna’s vaccine can be stored at around minus -20 degrees Celsius, roughly the temperature of a home freezer, according to Moncef Slaoui, the leader of the US effort to develop a vaccine against Covid-19. Moderna’s vaccine can also be stored in the refrigerator for 30 days before it expires.

“So it’s more manageable and much more available,” Slaoui said Tuesday.

These differences suggest that Pfizer’s vaccine may be used more for large institutions with established infrastructure like hospitals, while Moderna’s may be more useful for smaller facilities like a local chain or pharmacist.

Dosage and schedule: Moderna vaccine is given as two doses of 100 micrograms 28 days apart. Pfizer’s vaccine is given in two doses of 30 micrograms 21 days apart.

Age: If licensed, Moderna vaccine would be used in people 18 years of age and older, while Pfizer vaccine was licensed for people 16 years and older.

Is it sure?

The vaccine has a “favorable” safety profile, the FDA briefing document said, “without any specific safety concerns identified” that would prevent it from obtaining emergency clearance.

The most common side effects of the vaccine were pain at the injection site, fatigue, headache, muscle pain, joint pain and chills, according to the document. Swollen lymph nodes have also been reported.

Overall, “the frequency of serious non-fatal adverse events was low and without significant imbalance” between the group that received the vaccine and the group that received the placebo.

Study participant Yasir Batalvi, 24, told CNN he had a low fever, fatigue and chills after receiving the second injection of what he believed to be the real vaccine. He was fine the next morning.

Slaoui, the chief scientific adviser to Operation Warp Speed, said about 10-15% of immune subjects in the study would develop “fairly noticeable side effects.”

When can I get it?

The United States initially purchased 100 million doses of the Moderna vaccine, and last week agreed to purchase an additional 100 million doses. Moderna began manufacturing the first 100 million doses while clinical trials were underway, Health and Human Services said in a statement.

When can I get the coronavirus vaccine?

The vaccine still needs to be pre-authorized. The FDA advisory committee is meeting Thursday to discuss the emergency use authorization, and Slaoui said he expects the committee to approve it by Friday.

If that happens, he said he expects shipments to start 24 hours later so the vaccines will arrive at facilities by Monday morning.

Over 6 million doses of Moderna vaccine will be shipped to more than 3,200 locations, far more than the 636 locations to which Pfizer’s vaccines have been shipped.

From there, vaccines will be administered in an order established by national and local authorities. CDC vaccine advisers have recommended that health workers and residents of long-term care facilities be the first to line up for all coronavirus vaccines that get emergency approval.

CNN chief medical correspondent Dr Sanjay Gupta estimated that vaccines will generally be available in late spring or early summer.

CNN’s Jen Christensen, Elizabeth Cohen and Naomi Thomas contributed to this report.


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