Moderna Vs. Pfizer Vaccine

Throughout most of the world in the past year, the dominant story has been the COVID-19 pandemic. Globally, the virus has infected almost 112 million people and killed 2.49 million, while in the United States, more than 500,000 people have died from the disease so far. Currently, almost 2,000 people die daily from COVID-19, which is down from the high of 3,000 daily in mid-January.

The good news is that the death rate is expected to decline in the near future as more people become vaccinated. Last December, the Food and Drug Administration authorized the use of vaccines developed by Pfizer and Moderna. Both vaccines have been deemed highly effective in warding off the most severe effects of COVID-19 including hospitalization and death, but there are some differences that may make you prefer one over the other.

A Snapshot of the COVID-19 Pandemic

After the SARS-CoV-2 virus was first identified in Wuhan, China in December of 2019, COVID-19 has spread to every corner of the globe. COVID-19 is an airborne disease that is spread from person to person by exhaled respiratory droplets.  The key to its rapid spread appears to be the absence of symptoms like coughing, sneezing or fever in infected persons, allowing unknowing virus transmission.

Although there are almost 112 million confirmed cases of COVID-19 around the world, some experts believe that the actual number of cases could be 780 million or 10 percent of the global population. Many cases go unconfirmed because symptoms are mild, or testing is unavailable.

In the U.S., more than 500,000 people have died from COVID-19, or almost 20 percent of all fatalities. The death rate is falling as a new administration pushes COVID-19 policy and more Americans adopt stricter social distancing practices like wearing masks, maintaining six feet of distance, and regular hand washing.

Similarities between the Moderna and Pfizer Vaccines

The rollout of the COVID-19 vaccines has stoked optimism that the end of the pandemic is in sight, but there are many challenges ahead. Although the Moderna and Pfizer vaccines are available, for the moment, only the most vulnerable are eligible. In most areas of the U.S., that means health care workers, essential workers, and those over the age of 65.

If you are among these eligible groups, then you should be pleased to know that both the Pfizer vaccine and the Moderna vaccine have very high efficacy.  The Pfizer vaccine has a reported 95 percent success rate in preventing COVID-19 infection, while the Moderna vaccine has an infection prevention rate of 94 percent. It should be noted, however, that neither virus has been tested in children or pregnant women.

Both vaccines appear to produce similar side effects in select patients, including:

  • Pain at the injection site
  • Fatigue
  • Headache
  • Muscle pain
  • Joint pain
  • Chills
  • Nausea
  • Vomiting
  • Fever
  • Swollen lymph nodes

It is not surprising that both vaccines have similar profiles because both were developed along similar lines. Both the Pfizer and Moderna vaccines use messenger RNA or mRNA to make a spike protein found on the outside of the SARS-CoV-2 virus. This spike protein activates the body’s immune system to make antibodies. These antibodies are present so if the COVID-19 virus enters the body, they can neutralize the invaders before an infection can occur.

In order to achieve optimal efficacy, both the Pfizer and the Moderna vaccines must be administered in the form of two injections. While the Pfizer vaccine requires at least 21 days between shots, the Moderna inoculation mandates 28 days between shots.

Although there is some level of immunity to COVID-19 conferred with the initial shot, it is only weakened protection. Only with the second shot will you reach peak immunization. There is some debate about the necessity of both injections, but there is a lack of evidence that only one shot confers long-term protection.

The Differences between Pfizer and Moderna

There are some minor distinctions between the Moderna and Pfizer vaccines.

  • Age of recipients—the Pfizer vaccine has only been approved for use with people 16 years of age or older, while the Moderna vaccine is only authorized for use with those 18 years or older. Both companies are currently testing their vaccines among children 12 or older.
  • Cold storage—both vaccines are vulnerable to heat. While the Pfizer vaccine must be stored at negative 94 degrees Fahrenheit, the Moderna vaccine requires negative 4 degrees for long-term storage.  Recent data suggests that there may be some flexibility in storage temperature for the Pfizer vaccine.
  • Use duration—the Moderna vaccine can be maintained in a typical refrigerator for 30 days after it is brought out of cold storage. The Pfizer vaccine may be stored in a refrigerator for only 5 days at this time.
  • Size of doses—the Pfizer injections contain 30 micrograms of vaccine each, while the Moderna shots each contain 100 micrograms of vaccine. The Moderna vaccine may be overusing its supply without any appreciable difference in efficacy; Moderna is looking into lowering its dosages.
  • Severe reactions—although both vaccines have been deemed “safe” by the FDA, there is still a minor risk of severe, life-threatening reactions known as anaphylaxis. About 2.1 cases of anaphylaxis occur per one million doses of the Moderna vaccine, while about 6.2 anaphylaxis cases arise per one million Pfizer vaccine doses. Most cases of anaphylaxis appear among people who have had serious allergic reactions before.

Getting Vaccinated

There is no clearly superior vaccine for COVID-19. Given the risks of severe hospitalization, transmission to loved ones and potential death, it is in everyone’s best interest to get vaccinated with whatever version is available to you first. After all, some protection is far better than none. It is also important to keep in mind that the vaccine manufacturers are also improving them continually so more robust vaccines should be coming online very soon.

Some people may worry that current vaccines do not fully immunize against all strains of COVID-19. While this is a legitimate concern, the best way to neutralize emerging variants is to immunize the public so that existing strains are starved of hosts, preventing the opportunity for the virus to mutate.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

M.D. Disclaimer: The views expressed in this article are the personal views of Robert Moghim, M.D. and do not necessarily represent and are not intended to represent the views of the company or its employees.  The information contained in this article does not constitute medical advice, nor does reading or accessing this information create a patient-provider relationship.  Comments that you post will be shared with all visitors to this page. The comment feature is not governed by HIPAA and you should not post any of your private health information.