Potential benefits of an additional COVID-19 booster dose

As more research comes to light, the definition of being fully-vaccinated against COVID-19 has changed over time.

In the beginning, a fully-vaccinated individual was defined as someone with two doses of the Pfizer or Moderna vaccines or one dose of the Johnson & Johnson vaccine. Once boosters were approved, the definition was expanded to include that extra shot.

Now, Pfizer and Moderna are seeking approval from the Food and Drug Administration for a second booster shot. Will the definition change again?

The protection that these vaccines provide fades over time. For example, if you got the second dose of the vaccine on January 1, the protection should become effective two weeks later. Depending on the vaccine, effectiveness against infection tapers down to about 80% to 90% after 100 days. And 200 days later, in July, the effectiveness has gone down to about 60% to 70%.

The waning effectiveness in vaccines called for booster doses, and the FDA approved booster doses last fall.

And those boosters wane down to 60% after about 4 to 5 months.

Health officials like Mark Fox of the St. Joseph County Health Department say that this is one reason for the need of an additional booster.

"It's the waning immunity from the vaccine or the booster and the recognition that there are more transmissible variants that are coming or will be coming sometime in the future,” Fox said.

In addition to waning vaccine effectiveness, Fox says that Pfizer and Moderna are pushing for a second booster due to another factor: new COVID variants.

The Omicron sub-variant--or the BA.2 variant--is a more transmissible version of Omicron which is causing an uptick in cases in Europe and Asia. In the Midwest, however, the variant accounts for about 20% of COVID-19 cases as of last week.

Health officials claimed that Americans should not be concerned about the new variant yet.

In addition to decreasing infection and hospitalization, an additional vaccine would deter the spread of new variants like the BA.2 variant.

Even if the new variant does not significantly impact the US, it’s likely that new variants could emerge within unvaccinated populations and spread throughout communities.

“The hope is that an additional booster would even reduce the risk of infection and be more protective against future variants,” Fox said.

Additional COVID-19 variants have kept healthcare workers under a blanket of constant strain over the past two years.

“The Omicron variant was more transmissible, more mild and still it had a significant impact on hospitalizations. And, so the impact on healthcare infrastructure will continue to be a threat without adequate protection,” said Dr. Fox.

While the BA.2 variant has not yet made any significant impacts in the US, Dr. Fox and other health officials say the best protection against it is to get vaccinated and to get a booster shot.

The effectiveness of COVID-19 infection wanes over time; however, hospitalization rates do not decrease nearly as much over time. It still protects against severe forms of COVID.