The reason you can’t compare Covid-19 Vaccines


Marlon M., Staff Writer

In early March, over 6,000 doses of the Johnson and Johnson Covid vaccine were to be shipped to Detroit, Michigan, but the mayor declined, saying,” Moderna and Pfizer are the best.” but is this really true?

Detroit’s mayor was referring to the vaccine’s efficacy rates. Pfizer and Moderna have high efficacy rates at 95 and 94 percent respectively, while Johnson and Johnson’s vaccine has an efficacy rate of just 66 percent. However, arguably, efficacy rates aren’t even the most important measure when it comes to how effective vaccines are.

Vaccine efficacy rates are tested with thousands of people, half getting the vaccine, half getting a placebo or a fake. Then, they are told to live their lives, while scientists monitor whether or not they get Covid-19 over several months.  For example, in the Pfizer clinical trials, 43,000 people took part in the study, and 170 received Covid-19 over the testing period. If the number of people who contracted the vaccine is the same between the two groups, the vaccine would have a 0 percent efficacy rate. However, if all of the cases were from those who got the placebo, the vaccine would have a 100 percent efficacy rate. This means that those who received the vaccine were 95 percent less likely to contract the virus.

One big misconception about efficacy is that if the rate is 95 percent, out of one hundred vaccinated people, 5 would get the virus. However, this is not true. Instead, the 95 percent applies to the individual, meaning that someone who has had the vaccine is 95 percent less likely to contract the virus than someone who hasn’t. This applies every time they come into contact with the virus. 

Every trial is conducted the same way, but not all trials are done under the same circumstances. For example, the Moderna vaccine trial was conducted during the summer, when there were the least Covid cases. Pfizer performed their trials around the same time. Johnson and Johnson, on the other hand, conducted their trials early fall to late winter, when there were more opportunities for subjects to come into contact with the virus. Furthermore, much of Johnson and Johnson’s clinical trials were done in other countries, such as Brazil and South Africa, right when new strains of Covid started appearing that the vaccine was not made to prevent. The only way to fairly compare the vaccines is to combine the clinical trials, all set under the same conditions, the same time, the same place. Only then can we know which vaccine is best. 

All in all, the main purpose of the vaccine is to prevent deaths and prevent those vaccinated from having severe symptoms. In the clinical trials of all of the vaccines, in no cases did anyone who received the vaccine die, while there were reported deaths in the group who received the placebo. 

In fact, the mayor of Detroit even apologized for his words, saying that he’d start taking Johnson and Johnson vaccines, and that,” Pfizer, Moderna, and Johnson and Johnson are all highly effective at what we care about most, which is preventing hospitalizations and deaths.” Instead of worrying about which vaccine you will receive, or which vaccine will prevent you from any Covid infection, think, “Which one will keep me alive? Which one will take us one step forward to ending the pandemic?” I hate to be a spoiler, but the answer is: all of them.