By IDSE News Staff

The FDA expanded its emergency use authorizations (EUAs) for the Moderna and Johnson & Johnson (J&J) COVID-19 vaccines to allow booster doses for eligible populations.

The agency is allowing a single booster dose of the Moderna COVID-19 vaccine, to be given at least six months after completion of the primary series to individuals:

• 65 years of age and older; 
• 18 through 64 years of age at high risk for severe COVID-19; and 
• 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2.
  

The Moderna COVID-19 single booster dose is half the dose that is administered for a primary series.

The FDA is also allowing a single booster dose of the J&J (Janssen) COVID-19 vaccine given at least two months after completion of the single-dose primary regimen to individuals 18 years of age and older.

“The amendments to the emergency use authorizations to include a single booster dose in eligible populations are based on the available data and information, and follows the input from the members of our advisory committee who were supportive of the use of a booster dose of these vaccines in eligible populations,” said Peter Marks, MD, PhD, the director of the FDA’s Center for Biologics Evaluation and Research.

Pfizer and BioNTech have already received authorization to give boosters for their COVID-19 vaccine (Comirnaty), which can be given at least six months after completion of the primary series to people 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2.

In addition, the FDA will allow a heterologous, or “mix and match,” booster dose in eligible individuals following completion of primary vaccination with a different COVID-19 vaccine.

“We are also taking action today to include the use of mix-and-match boosters to address this public health need. We will work to accrue additional data as quickly as possible to further assess the benefits and risks of the use of booster doses in additional populations, and plan to update the health care community and public with our determination in the coming weeks,” Dr. Marks added.

Moderna Data

To support the authorization for emergency use of a single booster dose of the Moderna COVID-19 vaccine, the FDA analyzed immune response data from 149 participants ages 18 years and older from the original clinical studies who received a booster dose at least six months after their second dose, and compared it with the immune responses of 1,055 study participants after completing their two-dose series. The antibody response of the 149 participants against SARS-CoV-2 virus 29 days after a booster dose of the vaccine demonstrated a booster response.

The FDA also evaluated an additional analysis from Moderna comparing the rates of COVID-19 accrued during the delta variant surge during July and August 2021, which suggested there is a waning of vaccine effectiveness over time.
Safety was evaluated in 171 participants 18 years of age and older who were followed for an average of approximately six months. The most commonly reported side effects by the clinical trial participants who received the booster dose of the vaccine were pain at the injection site, tiredness, headache, muscle and/or joint pain, chills, swollen lymph nodes in the same arm as the injection, nausea and vomiting, and fever. Of note, swollen lymph nodes in the underarm were observed more frequently following the booster dose than after the primary two-dose series.

Ongoing analyses from the FDA and CDC safety surveillance systems have identified increased risks for inflammatory heart conditions—myocarditis and pericarditis—following vaccination with the Moderna COVID-19 vaccine, particularly following the second dose. Typically, onset of symptoms has occurred a few days following vaccination. The observed risk is higher among males under 40 years of age, particularly males 18 through 24, than among females and older males.

J&J Data

The authorization for emergency use of a single booster dose of the Janssen COVID-19 vaccine is based on the FDA’s evaluation of immune response data in 39 participants from a clinical trial including 24 participants who were 18 through 55 years of age and 15 participants who were 65 years of age and older. The study participants received a booster dose approximately two months after their first dose, and the results demonstrated a booster response.

Overall, approximately 9,000 clinical trial participants have received two doses of Janssen COVID-19 vaccine administered at least two months apart, and of these, approximately 2,700 have had at least two months of safety follow-up after the booster dose. Janssen’s safety analyses from these studies have not identified new safety concerns.

Earlier analyses from the FDA and CDC safety surveillance systems suggest an increased risk for a serious and rare type of blood clot in combination with low blood platelets following administration of the Janssen COVID-19 vaccine. This serious condition is called thrombotic thrombocytopenia syndrome (TTS). People who developed TTS after receiving the vaccine had symptoms that began about one to two weeks after vaccination. Reporting of TTS has been highest in females ages 18 through 49 years. In addition, safety surveillance suggests an increased risk for a serious neurologic disorder called Guillain-Barré syndrome, occurring within 42 days following receipt of the Janssen COVID-19 vaccine.

Heterologous Boosters

The authorization for heterologous boosters follows a presentation of clinical trial data from the National Institute of Allergy and Infectious Diseases, and a discussion with the Vaccines and Related Biological Products Advisory Committee, along with the agency’s evaluation of the available data. The FDA determined that the known and potential benefits of the use of a single heterologous booster dose outweigh the known and potential risks of their use in eligible populations.

A single booster dose of any of the COVID-19 vaccines may be administered as a heterologous booster dose following completion of primary vaccination with a different COVID-19 vaccine. The eligible populations and dosing interval for a heterologous booster dose are the same as those authorized for a booster dose of the vaccine used for primary vaccination.

For example, Janssen COVID-19 vaccine recipients 18 years of age and older may receive a single booster dose of Janssen COVID-19 vaccine, the half-dose Moderna or Pfizer-BioNTech COVID-19 vaccine at least two months after receiving their Janssen COVID-19 vaccine primary vaccination.

The CDC’s Advisory Committee on Immunization Practices will make practice recommendations for the boosters and heterologous dosing at today’s meeting. 

“As the pandemic continues to impact the country, science has shown that vaccination continues to be the safest and most effective way to prevent COVID-19, including the most serious consequences of the disease, such as hospitalization and death. The available data suggest waning immunity in some populations who are fully vaccinated. The availability of these authorized boosters is important for continued protection against COVID-19 disease,” said acting FDA Commissioner Janet Woodcock, MD.