COVID-19 mRNA vaccines have been shown to be around 90% effective in preventing serious illness or death, which means they are not foolproof. Why do vaccinated people get COVID? An expert in virology and infectious diseases clarifies the reasons why there are these so-called “revolutionary” cases.
It is essential to complete the scheme
For two-dose vaccines to reach their maximum level of effectiveness, it is necessary to apply both injections. In an article published in The Conversation, Dr. Lara Herrero, a researcher in virology and infectious diseases at Griffith University, explains that after receiving the first dose of the Pfizer vaccine, for example, you are 33% less likely to get COVID, including the Delta variant; but after the second dose, the chances decrease to 88%.
In addition, the probability of becoming seriously ill and requiring hospitalization is also reduced. Hence the importance of completing the immunization schedule.
However, data from the United States Centers for Disease Control and Prevention (CDC) show that to date 56.3% of the population has received a dose of the available vaccines, against 48.8% who have been fully vaccinated.
Vaccines do not kill the virus
Dr. Herrero explains that vaccines do not kill the virus, but rather stimulate a person’s immune system to generate antibodies that defend against infection and prevent the pathogen from causing serious illness or death. The immune response can vary from person to person based on many factors, such as general health, diet, stress levels, age or physical activity, among others.
To properly stimulate the immune system, it is necessary to complete the vaccination schedule, since the antibodies generated decrease after the first dose and are reinforced with the second.
Some of the infected people were exposed to the virus before their immune systems were able to fully develop antibodies, or their immune systems reacted weaker. Nonetheless, the vast majority of vaccinated people who have contracted COVID-19 have reported mild symptoms with a shorter duration.
Those vaccinated can transmit the virus
Even without symptoms, a vaccinated person can pass the virus to another unvaccinated person. According to the data of Herrero, people vaccinated with Pfizer are 50% less likely to transmit the virus to an unvaccinated person. If both people are vaccinated, this probability drops dramatically. In contrast, an unvaccinated person who contracts the virus will most likely spread it.
Mutations of the virus like Delta have been shown to be more contagious and cause severe symptoms more quickly. And while drug companies like Pfizer and Moderna are doing research to make their vaccines effective against the variants, the only way to stop mutations is for most people to get vaccinated as soon as possible.
“To help fight COVID-19, the best we can do is minimize the spread of the virus. This means get vaccinated when you can, make sure to maintain social distancing when necessary, and get tested if you have any symptoms”, Concludes the expert.
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.