NCT05567952
A small number of people who have COVID-19 experience a return of COVID-19 symptoms after initially feeling better.
This clinical trial is evaluating if an additional 5-day course of PAXLOVIDTM may provide benefit for adults and children at least 12 years of age with rebound of COVID-19 symptoms.
The development of safe and effective treatments is invaluable in the fight against COVID-19.
If your COVID-19 symptoms return after completing an initial 5-day course of PAXLOVID treatment, please consider this clinical trial. By joining this study, you will help Pfizer understand why some people experience a rebound of COVID-19 symptoms and may need an additional 5-day course of PAXLOVID.
Who may participate
Each clinical study has its own guidelines for who can participate, called eligibility criteria. However, only the research study staff can determine if you qualify to enroll in the study.
What to expect
About PAXLOVID
About PAXLOVID
PAXLOVIDTM is a combination of the medicines nirmatrelvir and ritonavir.
PAXLOVID has not been approved, but has been authorized for emergency use by FDA under an EUA, for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing at least 40 kg) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death.
The emergency use of PAXLOVID is only authorized for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of drugs and biological products during the COVID-19 pandemic under Section 564(b)(1) of the Act, 21 U.S.C. § 360bbb-3(b)(1), unless the declaration is terminated or authorization revoked sooner.

About COVID-19 symptom rebound
About COVID-19 symptom rebound
COVID-19 symptom rebound is a return of (or incomplete recovery from) COVID-19 symptoms that occurs in a small percentage of people, COVID-19 symptom rebound is not a separate infection caused by a re-exposure to COVID-19.
A previous study of high-risk participants who were treated with PAXLOVIDTM found a small number of participants (0.8%) experienced a return (rebound) of COVID-19 signs/symptoms after completing treatment. These participants’ symptoms initially improved with PAXLOVID, but later returned or worsened an average of 9 days after completing treatment. In most cases of COVID-19 rebound, symptoms are mild and do not increase the risk of severe illness or hospitalization.

Frequently asked questions
How long will I be enrolled in this study?
About 24 weeks (6 months).
How likely am I to receive PAXLOVID as part of this study?
Participants will be randomly assigned to receive the study drug PAXLOVIDTM (nirmatrelvir/ritonavir) or placebo (drug with no active ingredient) and ritonavir. This means that you are twice as likely to receive PAXLOVID than not. Neither you nor the study doctor will know what you have been assigned to receive.
How often will I need to attend study visits?
You will need to attend at least 10 study visits over about 6 months. Your first visit will be in-person at the study site. The next 7 visits may be a combination of in-clinic or at your home. Your last 2 appointments will be 3-month and 6-month follow-up phone calls.
What if I change my mind about participating?
Your participation in this study is completely optional (your choice). You can choose to leave the study at any time, for any reason.
What are possible side effects?
All clinical trials and treatments come with some risks. Your study doctor will discuss all the possible risks and benefits of participating in this study with you before you choose to enroll.
Does it cost anything to participate?
No, the study treatment and study-related procedures will be provided at no cost to you.