On December 11, 2020 the FDA approved an emergency use authorization for the two-shot COVID-19 vaccine created by Pfizer in the United States. This was followed by the two-shot vaccine created by Moderna approved on December 18, 2020 and the Johnson and Johnson single shot vaccine approved on February 27, 2021. Since the Pfizer authorization there have been many questions that have been circulating about the vaccines, including whether an individual that was already infected with the SARS-CoV-2 virus should seek out vaccination when it becomes available to them. At this time, the CDC recommends that all individuals within their recommended guidelines should receive their vaccination when it becomes available to them regardless of prior COVID-19 infection.
What is known about immunity after COVID-19 infection?
It is not fully understood how long immunity after infection lasts. One study has shown immunity for up to eight months but no other studies have been able to corroborate this timeline due to the relatively new development of the virus. Other coronaviruses have been known to induce short immunity after infection, this is of particular concern for those who have had asymptomatic infections since they may have had too low of a viral load to induce much of an immune response. A second infection soon after severe disease caused by COVID-19 has been proven to be rare, however, it has occurred on several occasions in different patients.
What is known about immunity after COVID-19 vaccine?
Since December the FDA has approved for emergency authorization two mRNA vaccines, Pfizer and Moderna and one DNA vaccine, Johnson and Johnson. The Johnson and Johnson DNA vaccine was shown to be 72% effective at preventing COVID-19 infection within the United States and 85% effective at preventing severe disease if infected. The Moderna and Pfizer mRNA vaccines have been shown to be 94% and 95% respectively effective against infection of the SARS-CoV-2 virus. With that said, researchers are not certain how long immunity lasts after vaccination. It is currently believed that there may have to be annual boosters to induce immunity annually. But scientists urge everyone to be vaccinated now to at least create mass short term immunity to limit the spread of the virus.
So do you need to be vaccinated if you were already infected?
The short answer to this is, yes. The scientific community, including the CDC, is recommending that all individuals that are within the guidelines to receive the vaccine should receive it regardless of prior infection. The CDC has determined that individuals receiving vaccination after infection are at no increased risk, but must wait until they are no longer symptomatic after the quarantine period. Scientists recommend that even those previously infected with the virus to be vaccinated because the length and strength of natural immunity are unknown. There have been several cases of infection for a second time after infection and there are not enough studies to support a definitive length to immunity nor the strength of the immunity after natural infection. Researchers urge that everyone take the cautionary route and become vaccinated as soon as it is available to them and they are not symptomatic from infection as to ensure a higher level of immunity caused by the vaccinations.