Why vaccinated people can still get sick with the omicron variant

With so many health experts, public officials, and organizations pushing for COVID-19 vaccinations and boosters, you may be wondering why vaccinated individuals are still occasionally getting sick with COVID-19.

The answer takes some explanation, with the help of Dan Diekema, MD, MS, hospital epidemiologist and infectious disease specialist.

It’s also a good time to remind ourselves that we must recommit ourselves to follow safety standards in our community: Be aware and committed to mask wearing, social distancing, and avoiding gatherings.

By focusing on our safety measures during this surge in cases due to the omicron variant of COVID-19, we can each make a difference.

The purpose of vaccinations

First, we must understand the purpose behind vaccinations. In general, vaccinations of any kind (from COVID-19 to chicken pox) are intended to lessen the likelihood that an individual contracts a certain illness. But the most important goal of a vaccine, and what is essential to know about the COVID-19 vaccine, is that it reduces the severity of the illness within an individual if they do get sick.

Initial reports show that receiving only one or two doses of an mRNA vaccine, like the Pfizer-BioNTech or Moderna vaccines, does not reduce the likelihood of infection against omicron as much as it does against previous variants. However, receiving a booster greatly helps both prevent the likelihood of infection with the omicron variant and reduces the severity of illness if you do get sick.

So simply put, even though the vaccines won’t always keep you from catching the virus, they'll make it much more likely you end up with mild symptoms like congestion, a sore throat, and fatigue, rather than a hospital stay.

Omicron is highly contagious

Although early data indicates omicron does not cause more severe illness than previous variants, it does spread much more quickly.

Omicron appears to replicate more efficiently than previous variants, and if those infected with COVID-19 have high viral loads—i.e., the amount of virus in the airway—they’re more likely to pass the virus on to others, especially those who are unvaccinated or un-boosted.

Safety guidance

Expert advice for staying safe hasn’t changed in light of omicron. Wearing masks while indoors, avoiding gatherings and keeping your distance from others, and receiving a COVID-19 vaccination and booster remain the most effective ways to limit the spread of the virus.