When the COVID-19 pandemic began, it wasn’t widely predicted that we would still deal with it over a year later. While a few countries such as Australia and New Zealand have been able to eliminate the virus by altering their social behaviors, the rest of us are looking to vaccine technology to protect us. Currently, three vaccine types have been approved for use in the United States.
The Pfizer-BioNTech vaccine was the first to receive approval from the Federal Drug Administration (FDA) on December 11, 2020. It is approved for use in individuals aged 16 and older, and has proved to be 95% effective in preventing COVID-19 for those who have not previously contracted the virus. Research indicates that vaccine effectiveness is not altered by factors such as sex, race, ethnicity or body mass index (BMI). While it has shown to be just as effective in preventing the virus variant first detected in Great Britain, it may be less effective against the variant first detected in South Africa.
The Pfizer vaccine is delivered in two doses given 21 days apart. It is a messenger RNA (mRNA) vaccine, delivering a small piece of the SARS Cov-2 genetic code to the host cells of the body, acting as an instruction manual for the body to combat the virus. Symptoms of the Pfizer vaccine have reported to include chills, headaches, tiredness and pain and redness at the injection site. The Center for Disease Control (CDC) requires that vaccine recipients be monitored for 15 minutes after the shot, and for those who have severe allergies or are taking blood thinners to be monitored for 30.
About a week after the approval of the Pfizer-BioNTech vaccine, the Moderna vaccine received approval on December 18, 2020. It is approved for those 18 and older, and has proved to be 94.1% effective in those with no prior history of COVID contraction. It is indicated that the efficiency of the vaccine is not altered by factors such as sex, race and ethnicity, but the effectiveness drops to 86.4% in individuals aged 65 and older. The Moderna vaccine offers a key advantage over Pfizer-BioNTech in that it can be stored and shipped at regular freezer temperatures as opposed to the Pfizer vaccine which requires dry ice for proper storage.
The Moderna vaccine is delivered in two doses 28 days apart. Like the Pfizer vaccine, it is an mRNA vaccine, sending the instructions to combat the virus to the host cells. Side effects have been reported to include chills, headache, tiredness, and redness and pain at the injection site. The CDC requires recipients of the Moderna vaccine to be monitored for 15 minutes after the shot, while those with a history of severe allergies should be monitored for 30.
Most recently, the FDA approved the use of the Johnson & Johnson vaccine on February 27, 2021. This vaccine has an overall efficacy of 72%, but differs from both the Pfizer and Moderna vaccines in that it can be stored at refrigerator temperature and is delivered in a single dose, two factors which may make the Johnson & Johnson vaccine easier to deliver and administer.
Unlike the Pfizer and Moderna vaccines, the Johnson & Johnson vaccine is not an mRNA vaccine. Instead, it is a carrier vaccine, delivering genetic code to the host cells under the shell of an adenovirus which induces an immune response. Side effects of the vaccine include headache, fatigue, and pain at the injection site. The FDA notes that the side effects of the Johnson & Johnson vaccines are more mild than those of the Pfizer or Moderna vaccines.
In addition to the three vaccines that have been approved for use in the United States, there are two additional vaccines that show promise. First is the Oxford-AstraZeneca vaccine, which is approved for adults aged 18 and older in the United Kingdom and other countries. Like the Johnson and Johnson vaccine, it is a carrier vaccine which is stored at refrigerator temperatures. It is delivered in two doses, administered four to 12 weeks apart. It is around 60% effective.
Still under clinical trials is the Novavax vaccine. It is a protein adjuvant vaccine, containing a spike protein of the virus formulated as a nanoparticle, which stimulates an immune response. It is delivered in two doses, three weeks apart, and is 89.3% effective in adults aged 18 and older. While it is still under trial, the Novavaxx vaccine has shown no adverse side effects.