There are some anecdotal reports on social media today about Covid-19 infections rebounding a few days after taking Paxlovid. The rebound effects could be caused by reinfection, the biphasic effect of the virus, Paxlovid not clearing the infection completely, or by another unknown mechanism. If you are taking Paxlovid, then you should probably read up on this.
Looking for intel from #medtwitter and covid high risk folks here. My husband, who has an underlying immune dysfunction disorder, had covid, got paxlovid pretty quick, did well, tested negative (rapid antigen) 5 days ago, was asymptomatic. Now symptomatic and positive. 1/n
— Colleen Caleshu (@colleencaleshu) April 15, 2022
PSA I’ve now heard of several cases of a biphasic symptom and testing pattern for BA.2 from people that rapid test themselves liberally. They’re sick, they test positive, they feel better, they test negative, and a few days later symptoms come back and they’re positive again.
— Dr. Lisa Iannattone (@lisa_iannattone) April 18, 2022
1/ Close vaccinated/boosted relative with almost identical story.
Mild symptoms➡️+ test➡️paxlovid (high risk by age)➡️much better within 24 hours. Neg test on day 5. — Steve Joffe (@SteveJoffe) April 18, 2022
OMG. You’re the 2nd person I’ve read today with nearly my exact same situation! Tested + and felt crappy, started Paxlovid. By day 3-4, was feeling better and started testing – on rapid tests. Many tests (I also had a stockpile), 3 brands.
— Tara L (@TaraL3056) April 18, 2022
Omg! This happened to me too! I thought I was reinfected! Thank you for sharing. I’m triple vaxxed & my first infection was late March, + on 3/23, Paxlovid, – on 4/1 RAT & PCR, + again on 4/7, prescribed Paxlovoid again, -PCR & RAT on 4/13.
— Nike Knight (@NikeKnight2) April 19, 2022
Happened to me too! Negative Day 9 after Paxlovid, faint positive today Day 10 with cold symptoms.
— Critical research (@CriticalReview9) April 18, 2022
I know someone with the same story but when the symptoms returned 3 weeks later, they died within 24 hours
— Gazpacho PoPo (@baby2thfairy) April 18, 2022
Wish I had known this last week. I feel worse now than before I took it. https://t.co/aYrO2gs5S6
Author Alisa Lynn Valdes🖋 (@AlisaValdesRod1) April 21, 2022
Update on LC symptoms after Paxlovid: It has been 30 days since my first dose, and my headache symptoms have returned. Fatigue symptoms still gone. Though I was testing antigen- for a while, today I tested + again. Maybe I needed longer course; regardless, we need more research.
— Lav (@gemale10) April 26, 2022
Updated post to link this pre-print from Kalpana Gupta @CharnessMichael @JudithStrymish and Gary Stack.
Here’s the key figure, note cycle threshold on rebound. https://t.co/qBkChxUNsq https://t.co/XOIIP73lsk pic.twitter.com/0IPxiCkTbu
— Paul Sax (@PaulSaxMD) April 26, 2022
UPDATE 1 – 21st April 2022
Twitter and Reddit have been filled with patients and doctors sharing their experiences and hypotheses over the past few days, including John Donoghue, a 71-year-old emeritus physics professor in Amherst. “We had three cases in the house with the same pattern,” Donoghue said, in an interview.
Donoghue, his wife, and her 95-year-old mother all were infected with COVID in the last month. All three received Paxlovid, felt better, and tested negative on rapid tests for four or five days. Then their symptoms returned and each one tested positive again.
UPDATE 2 – 28th April 2022
“Our findings suggest that viral replication and COVID-19 symptoms may recur after very early treatment with NM/R before natural immunity is sufficient to fully clear SARS-CoV-2.”
UPDATE 3 – 30th April 2022
U.S. government researchers are planning studies of how often and why coronavirus levels rebound in some Covid patients who have completed a five-day course of treatment with Pfizer Inc.’s Paxlovid.
UPDATE 4 – 15th May 2022
Preprint: “We describe relapse of COVID-19 symptoms and SARS-CoV-2 viral load following nirmatrelvir/ritonavir (NM/R) in 8 non-immunocompromised patients aged 31 to 71-years-old.
Most patients improved rapidly after treatment with NM/R and had negative antigen or PCR tests prior to relapse on Days 9-12 of their illness. Relapse symptoms were described most frequently as cold symptoms, though some patients experiencing a recurrence of fatigue and headache. All relapses resolved without additional antiviral treatment. Viral load during relapse was comparable to levels during initial infection.
Sequencing in three patients indicated that relapse was not due to a treatment-emergent mutation or infection with a different viral strain. One patient transmitted SARS-CoV-2 to two family members during relapse. The presence of high viral load and the occurrence of one transmission event suggest that patients with relapse should isolate until antigen testing is negative.”
NOTE: The original tweet by Andrew Teman that started this thread has since been made private