COVID-19 Impact on Georgia Latest Articles

By Mary Elizabeth Dallas

Millions of Americans are rolling up their sleeves for updated COVID booster shots. Health officials monitoring the rise of new Omicron subvariants are trying to do something they’ve not been able to achieve since the pandemic began: Stay one step ahead of the virus.

The Centers for Disease Control and Prevention (CDC) approved the U.S. Food and Drug Administration's (FDA) decision to authorize reformulated versions of the Moderna and Pfizer-BioNTech COVID vaccines. The updated shots are known as "bivalent" vaccines because they are designed to target the highly contagious omicron variants that are currently responsible for nearly all new infections in addition to the original strain of the virus. The reformulated shots could help bolster protection ahead of an anticipated new wave of infections in the coming months.

“The updated COVID-19 boosters are formulated to better protect against the most recently circulating COVID-19 variant. They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants. This recommendation followed a comprehensive scientific evaluation and robust scientific discussion," said CDC Director Rochelle P. Walensky, M.D., M.P.H. in a September 1 news release. "If you are eligible, there is no bad time to get your COVID-19 booster and I strongly encourage you to receive it.”

The updated Moderna and Pfizer boosters are available for people ages 6 months and older. Those eligible can receive an Omicron booster if its been at least two months since they completed their primary series or received a booster, including children ages 6 months through 5 years old who received the two-dose Moderna primary series. Kids ages 6 months through 4 years old who are haven't yet completed their three-dose Pfizer primary series can receive the omicron booster as their third dose. 

With flu season underway, anyone eligible can safely get their flu shot and their Omicron booster at the same time. Keep in mind, it takes about two weeks to develop protective antibodies after vaccination.

Why an updated booster is needed
Omicron has spawned two more subvariants, known as BA.4 and BA.5, that have been detected in dozens of countries around the world. Together, they are responsible for nearly all new U.S. infections as of late-August. Experts contend new cases may surge as summer gives way to fall—when temperatures drop, protection against COVID wanes, and more people head back indoors.

“That combination of waning immunity, combined with the potential emergence of novel variants during a time this winter when we will move inside as a population, increases our risk of a major COVID-19 outbreak and for that reason we have to give serious consideration to a booster campaign this fall to help protect us during this period from another COVID-19 surge,” Dr. Marks said during the FDA vaccine advisory committee meeting.

Omicron and its close cousins are less severe but more contagious than previous variants. They’re also more likely to successfully evade existing vaccines and treatments. Complicating matters, nearly three years of data shows that COVID immunity—from vaccination, infection, or both—wanes over time.

A February 2022 CDC study showed that vaccine effectiveness against COVID-related emergency room visits and hospitalizations was improved by a third dose, but that protection declined over time. After four months, during the first Omicron wave, efficacy against urgent care visits fell from 87 percent to 66 percent and effectiveness against hospitalizations dropped from 91 percent to 78 percent.

Research suggests protection also wanes among those who have recovered from COVID. Another May 2022 CDC study found that vaccine protection against hospitalization among those who are re-infected fell to 68 percent after three doses. Efficacy against hospitalization fell to 35 percent among those who only received two doses of the vaccine.

So, while getting an initial booster improves protection against hospitalization, the original vaccines were designed to protect against the original COVID strain, which is no longer in circulation.

During the latest trials, the Omicron-specific boosters made by Pfizer and Moderna targeted both the original COVID strain as well as the first Omicron variant, known as BA.1. Data from both drug companies suggest their combination, or bivalent, vaccines trigger a stronger immune response against BA.1. Researchers noted the response was even greater than just another dose of the original vaccine.

Since the modified vaccines were formulated to target an older Omicron relative, they did not perform as well against BA.4 and BA.5—the Omicron variants that have since emerged. Still, the modified vaccines triggered a stronger immune response against these newer variants than the initial vaccine.

What happens next
Based on this data, the FDA advised both companies to update their modified vaccines so that they target BA.4 and BA.5—not BA.1. The hope was that by acting months in advance, the updated booster would ready by fall.

“None of us has a crystal ball, and we are trying to use every last ounce of what we can from predictive modeling and from the data we have that’s emerging to try to get ahead of a virus that has been very crafty,” Marks said.

Regulatory officials have also asked Pfizer and Moderna to continue trials, including their updated BA.4 and BA.5 boosters.