Pfizer vs Moderna Vaccines

Pfizer vs Moderna Vaccines

Ayden Nguyen, Writer

Currently, there are two vaccines available to the United States, one made by Pfizer/BioNTech and one made by Moderna. The two vaccines both work well but there are some differences. For instance, the Pfizer vaccine is eligible for people 16 years or older while the Moderna vaccine is designated for people 18 years or older.


Both vaccines have been proven to be very effective. The Pfizer vaccine has been shown to be 95 percent effective while the Moderna vaccine was 94.1 percent effective. The efficacy of the vaccines appeared to be consistent over all age, ethnic, and racial groups. However, it is not known if the vaccine is at all effective against the new Coronavirus variant.


Both vaccines require 2 doses, a priming dose then a booster shot. The Moderna vaccine needs 4 weeks between doses while the Pfizer vaccine needs 3 weeks. Additionally, Pfizer uses 30 micrograms of vaccine per dose while the Moderna vaccine uses 100.


Vaccines that cause a range of short term side effects can be classified as reactogenic. Both these vaccines can be categorized as reactogenic. Common side effects include soreness where the injection occurred, fatigue, headache, and in some cases a fever. These side effects have happened mainly after the second dose. Additionally, younger adults, who have stronger immune systems, tend to experience more side effects than older adults. These side effects are not signals that the vaccine is unsafe or non-effective but rather, a sign that your immune system is reacting to the vaccine. There have been some reports of allergic reactions to the Pfizer vaccine. These were not seen during the clinical trials and it remains to be seen if it will happen with the Moderna vaccine.


Neither vaccine has been tested on women who are pregnant or breastfeeding. Moderna has conducted such tests on animals and saw no sign that the vaccine could harm the pregnancy. Pfizer also has data from tests on animals and didn’t see any concern. But, there is not sufficient data to determine whether or not it is safe for pregnant and breastfeeding women. Peter Marks, FDA director of the Center for Biologics Evaluation and Research, stated that if you are pregnant, you should check with your physician to consider the benefits and risks before getting vaccinated.


Both vaccines must be stored at cold temperatures when they are distributed and at the places where they will be administered. But, the Moderna vaccine will be much easier to store and use than the Pfizer vaccine. Moderna’s has to be shipped and stored at -4 degrees Fahrenheit while Pfizer’s has to be shipped and stored at -94 degrees. The Moderna vaccine can be stored in a regular refrigerator freezer while the Pfizer vaccines are required to be stored in special ultracold freezers. Most doctor offices and pharmacies do not have these. Furthermore, after thawing, Pfizer’s vaccine has to be used within 5 days. On the other hand, Moderna’s vaccine can stay in the refrigerator for 30 days and last 12 hours at room temperature.


The storage temperature is not the only flaw to Pfizer’s vaccine. The minimum number of doses a place can order is 975. A few of those might be enough for a large hospital but there are lots of places that don’t require the need for 975 doses. Keep in mind that the vaccine needs to be stored in ultracold freezers which most places don’t have, further limiting the locations the vaccine can be used. Moderna’s vaccine is much easier to distribute because its minimum order number is 100 doses.


How long the vaccine protects you is not yet known. It will take periodic blood samples to see the level of antibodies in their body. But, a decline in antibodies does not mean a lower level of protection.


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