The Food and Drug Administration (FDA) on Thursday approved the latest COVID-19 vaccines from Pfizer and Moderna, set to soon be distributed to the wider American public as virus cases surge this season.
These new vaccines are designed to combat the KP.2 strain, a derivative of the highly transmissible JN.1 subvariant of Omicron, which has spread widely in the United States since early this year. As of May, KP.2 was the predominant strain, although it now accounts for only about 3% of current infections in the United States, according to the most recent statistics from the Centers for Disease Control and Prevention (CDC).
Both Pfizer and Moderna have indicated that their vaccines targeting the KP.2 strain are more effective at eliciting strong immune responses against other prevalent subvariants such as KP.3 and LB.1 than previous vaccines targeting the homicron XBB.1.5 strain.
Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, stressed the importance of updating vaccinations because of waning immunity from previous infections and vaccinations. He strongly urged eligible individuals to get the new vaccine for greater protection against the variants currently circulating.
The CDC has recommended that all children over 6 months of age receive the updated COVID vaccine along with a flu shot this season. The newly approved vaccines from Pfizer and Moderna are authorized for children ages 12 and older, with emergency use authorization extended to children ages 6 months to 11 years.
Pfizer has announced that it will begin shipping its latest vaccine immediately, with availability expected in pharmacies, hospitals and clinics within the next few days. Similarly, Moderna has said its vaccine will be available soon.
Moderna CEO Stephane Bancel stressed the importance of keeping vaccinations up to date as a key measure to protect against serious illness. He welcomed the FDA’s swift review and encouraged discussions among individuals and healthcare providers about getting the updated COVID-19 vaccine along with the flu vaccine this fall.
The FDA’s approval of these vaccines comes ahead of last year’s vaccinations, which were authorized on September 11.
The ready availability of these vaccines provides some reassurance amid this summer’s relative spike in virus cases, as evidenced by “high” or “very high” levels of Covid detected in wastewater in nearly every state, a measure that offers insight into the prevalence of the virus now that testing rates have declined.
While other virus metrics are rising, they remain significantly below peak levels of the pandemic. The positivity rate for COVID tests increased slightly to 18.3% for the week ending Aug. 10, up from 17.9% the week before, the CDC reported. Hospitalizations are also up, with about four cases per 100,000 people, up from one per 100,000 in May, the lowest rate since the pandemic began.
As vaccinations begin and immune responses develop, which usually takes about two weeks, the current surge in cases may begin to decline.
Federal health officials continue to expect annual updates on COVID-19 vaccines, similar to annual updates on flu vaccines, as the virus evolves and immunity from previous vaccinations or infections wanes.
Despite the availability of vaccines, it remains to be seen how many Americans will opt for the updated vaccination in the coming months. According to CDC data through early May, only about 22.5% of U.S. adults had received the latest round of vaccinations that began last fall.
Many Americans who skipped new rounds of COVID-19 vaccinations cited a lack of concern about the virus or being too busy as reasons for not getting the latest booster, a November survey by KFF, a health policy research organization, found.
In early June, the FDA initially asked vaccine makers to focus on the JN.1 strain, but later told them to focus on KP.2 “if feasible,” putting companies like Newvax, which had sought approval for a JN.1 vaccine, at a disadvantage. Novavax is still in talks with the FDA and expects to authorize its vaccine in time for the main U.S. vaccination season, saying its vaccine offers protection against several JN.1 descendants, including KP.2.3, KP.3, KP.3.1.1 and LB.1.
Unlike the mRNA technology used by Pfizer and Moderna, which allows for rapid updates, Novavax uses a protein-based technology, a decades-old method also used in routine vaccinations against hepatitis B and shingles, making it slower to adapt to new strains.