In early tests, Pfizer’s COVID-19 Vaccine proved effectiveness up to 90% – but why are more tests needed?

Preliminary results from Pfizer’s late-stage vaccine trial suggest that the vaccine can prevent COVID-19. The promising development comes at a time as the United States reached a grim moment of almost 10 million coronavirus cases, with around 238,000 deaths reported. The company plans to seek authorization for emergency use from the Food and Drug Administration (FDA) this month.

Renown pharmaceutical firm Pfizer stated on Monday that an early analysis of data from its late-stage COVID vaccine trial suggests that the vaccine can prevent COVID-19 in people who have not been exposed to the virus earlier.

This promising development comes as the United States reached a grim milestone of 10 million coronavirus cases with more than 238,000 deaths. Around the world, more than 1.2 million people died due to COVID-19.

According to a news release, Pfizer COVID 19 vaccine has been tested on more than 43,000 people and no serious safety concerns or side effects were found.

In the phase 3 trial, people were randomly assigned to receive two doses of the vaccine in a difference of 28 days or an inactive placebo. Here, participants were not aware which group they were in. Seven days after the second dose was given, the vaccine had an efficacy of more than 90 percent.

Dr. Sunil Sood who is the chair of pediatrics and specialist in infectious diseases at Northwell Health’s Southside Hospital believes the preliminary results are quite promising. According to him: “This shows that most people who developed infection were placebo recipients and most of those who got the actual vaccine did not get infected.”

The company stated that it plans to seek emergency use authorization from the Food and Drug Administration (FDA) by the third week od November.

By that time, researchers will be conducting follow-ups with participants for an average of 2 months after their second dose, as recommended by the FDA. Also, Pfizer further revealed that it expects to produce up to 50 million doses of the vaccine in 2020 and up to 1.3 billion doses in 2021.

There are still many questions about the Pfizer’s COVID-19 Vaccine

Dr. Carlos Malvestutto is an expert on infectious diseases at the Ohio State University Wexner Medical Center. He said that the interim results of Pfizer’s trial are very encouraging. According to him: “Obviously, 90 percent protection is the level of protection that we would love to have for all vaccines.”

If the efficacy seen during the interim analysis holds through the remainder of the trial, it will exceed the 50 percent efficacy target which was set by the FDA for coronavirus vaccines. Ninety percent efficacy is also resembling the protection provided by other renown vaccines such as vaccines for Chicken pox, HPV and measles.

However, some researchers are yet to comment on the preliminary health results as not enough data has been released for them to comment on the preliminary results.

Pfizer developed the vaccine in collaboration with German biotech company BioNTech, released the interim results in a news release instead of a peer-reviewed medical journal. The company plans to conduct a final analysis when it reaches 164 confirmed cases of COVID-19.

However, many questions about the COVID vaccine still need to be answered.

David Verhoeven, PhD, a researcher with the Nanovaccine Institute and an assistant professor of veterinary microbiology and preventive medicine at Iowa State University stated that the level of protection observed during the interim analysis looks promising. However, he is also unsure of how long it can last.

According to him: “We know from natural [coronavirus] infection that immunity may wane in 4 to 6 months. [If this happens with the vaccine]; you will likely need yearly booster shots.”

Also, it is unclear whether the vaccine can protect against severe disease, which also increases the risk of dying from COVID-19. According to Dr. Malvestutto: “If researchers can show that people who are vaccinated and still get COVID-19 have milder disease, that would be huge winner.”

For the interim analysis, researchers only looked at whether the vaccine prevented symptomatic coronavirus infection, which includes mild and moderate cases. Keeping the recent surge in coronavirus cases stateside, Dr. Malvestutto says researchers will likely see enough severe cases to know if the vaccine helps this group of people.

He also later revealed that longer-term data about the vaccine’s safety is needed despite Pfizer meeting the minimum recommendations of safety assessment set forth by the FDA. Researchers plan on doing follow-ups for 2 years after their second dose. The Center for Disease Control and Prevention also routinely monitor the safety of vaccines approved by the FDA.

Pfizer’s vaccine was not developed as part of Operation Warp Speed, which is the United States Government’s coronavirus vaccine effort. However, the administration of President Donald Trump did agree in July to buy at lease 100 million doses. Under such an arrangement, Americans would receive the vaccine without any charges (vaccine for COVID 19).

Multiple Pfizer’s COVID-19 Vaccine are needed to control the pandemic

Pfizer did make the first vaccine to show promising results in a phase 3 trial, 10 other vaccines have reached this stage. These include a wide range of vaccine technologies. Pfizer’s vaccine uses messenger RNA or mRNA to elicit an immune response in people who received the vaccine. Moderna’s vaccine is also based on this technology.

This newer vaccine platform is being tested for use against other infectious diseases like the seasonal flu, Zika virus and rabies. None have been approved yet for use in people. Other technologies being used against the coronavirus include vaccines based on a DNA platform, weakened or inactivated versions of the virus, viral protein subunits, particles resembling the virus or delivery of a coronavirus protein through another virus.

Some of these technologies are new while others have been around for a long time. According to Dr. Sood: “With both old and new technologies being used, out chance of getting several successful vaccines is actually very high.”

Given the size of the pandemic, multiple vaccines might be needed. According to Dr. Malvestutto: “We’ll need more than one vaccine that has good protection and is safe and well tolerated because that’s the only way we’re going to be able to really get control of this pandemic in a reasonable time.”

However, finding a safe and effective vaccine is just one hurdle that needs to be overcome. Vaccines would still need to be manufactured and distributed. Vaccines of Moderna and Pfizer require an ultra-cold storage, adding more complications to the distribution.

Convincing people to actually get vaccinated is itself another serious challenge. An Axios-Ipsos survey from October revealed that only 2/3rds of Americans would get a coronavirus vaccine if it is approved by the FDA.

According to Dr. Malvestutto: “You can have the most amazing vaccine but if people don’t take it, then that’s obviously not going to help.”

A STAT-Harris poll however, suggests that people may be more than willing to get vaccinated provided its efficacy rate is satisfactorily high. But, Dr. Sood is of the view that more work needs to be done so people can be convinced. The hard hit African American and Hispanic communities are hard-hit groups and convincing them is a must.

He states:

“A lot of community action at the local grassroots levels will be needed to explain the safety and efficacy of the vaccine, as well as the importance of getting the vaccine.”

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