UPDATE: A #coronavirus patient is considered contagious as long as they carry "replication-competent" virus. Based on limited CDC data, patients with severe immune impairment are thought to be contagious for up to 20 days after onset of COVID19 symptoms. This may soon be revised:
We've known that patients with weakened immune systems can remain contagious for up to twice as long as those without immune impairment (20 days vs. 10 days) and these findings have informed transmission-based precautions around the country.
But 20 days may be insufficient.
A new study of immunocompromised #COVID patients found that some remain potentially contagious far longer than previously thought: 15% had replication-competent virus after 20 days.
Key finding: 1 patient grew virus in culture 61 days after symptom onset. nejm.org/doi/full/10.10…
These unique patients received allogeneic hematopoietic stem-cell transplants or CAR T-cell therapy within the previous 6 months & remained negative for antibodies to coronavirus. Their immune systems were severely compromised, which likely allowed virus to continue replicating.
Many people have weakened immune systems, but specific treatments (stem cell transplant) can produce defects in the immune system that allow #coronavirus to fester. With time, we'll create subcategories of patients with bespoke treatment, transmission, and quarantine guidelines.
Takeaway: For most of the pandemic, we've believed that severely immunocompromised patients remain infectious no longer than 20 days after symptom onset. We now know that a subset of these patients can shed viable coronavirus for 2 months. Isolation precautions should be updated.
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UPDATE: Operation Warp Speed won't hit its goal of 20 million Americans vaccinated against #coronavirus by the end of 2020. To improve the rollout, we should: 1) Look back, 2) Look ahead, and 3) Look in the mirror. My thoughts:
1. Look back: This isn't the first mass vaccination in the midst of an outbreak. In 1947, New York City inoculated millions against smallpox in a matter of days. How did they do it? Vaccination was available at more than 250 hospitals, clinics, police stations, and schools.
Vaccination was voluntary and free of charge. There was also a massive citywide doorbell-ringing campaign. As we become more comfortable with the safety of covid vaccines, we must increase outreach. Most don't know how or where they'll get vaccinated. vanityfair.com/culture/2013/1…
Hospitalized patients and research subjects often ask me about antibody treatments. They touch on a recurring theme: Many believe these treatments go unused because a) Doctors don't think to order them or b) We don't have the connections to acquire them. Here are key points: 1/
Monoclonal antibodies made by Regeneron and Eli Lilly are not authorized for patients who are hospitalized due to #COVID19. Trials have been stopped because antibodies don't help these patients. Nevertheless, many are distressed they're not being used. 2/ nytimes.com/2020/10/27/wor…
We've recognized the futility of giving antibodies to hospitalized patients for months, but only recently have we understood why: The timing of the antibody response is more important than the amount of antibody.
Early antibody response is crucial. 3/ medrxiv.org/content/10.110…
UPDATE: Vaccinologists like to say they breathe a sigh of relief after 3 million inoculations of a new vaccine. That's when we get a real handle on side effects. We'll soon reach that milestone with mRNA vaccines (Pfizer, Moderna). There's another phenomenon we should follow: 1/
It's important to determine if people are contracting #coronavirus after vaccination. The phase 3 trials that were the basis for emergency authorization looked at prevention of symptomatic disease; they did not assess prevention of transmission. 2/
This means people could, in theory, contract #coronavirus and transmit it to others after vaccination. But is this happening? Thus far, I've only heard of one case of a person contracting the virus after vaccination. (Are there more?) It happened in Texas. 3/
Here are 3 #COVID19 questions we're trying to answer: 1. Why do monoclonal antibodies fail hospitalized patients? Cocktails made by Eli Lilly & Regeneron may be useful for high-risk outpatients, but they don't help hospitalized patients. Why does the treatment setting matter? 1/
Part of this is timing. By the time someone shows up in the ER with symptoms, they may have been infected for a while (incubation is ~6 days). Most COVID treatments fail if they're given late in the course of disease and antibodies are no exception. They should be given early. 2/
But there are other theories to explain the failure: Antibodies may fail to efficiently penetrate the infected tissue of hospitalized patients. Or coronavirus may mutate to evade the monoclonal antibodies (these are called escape mutations). 3/ pubmed.ncbi.nlm.nih.gov/32540904/
COVID question doctors are wrestling with: Should patients with profoundly impaired immune systems receive monoclonal antibody therapies after contracting #coronavirus? 1/
These patients are often prioritized for antibody treatments (made by Regeneron and Eli Lilly). And this makes sense: Their immune systems are weak, and antibodies can potentially help fight infections. But there's an issue. 2/
A new hypothesis argues that patients with weak immune systems could serve as an incubator for viral mutations, leading to new strains like B.1.1. 7 that might be more transmissible. 3/
UPDATE: Coronavirus has mutated into a new variant, B.1.1.7, that has the world's attention because it may be more contagious.
Some thoughts on where this came from and how it impacts patient care: 1/
The novel #coronavirus typically acquires a mutation every few weeks. The new variant is interesting because it seemingly developed a bunch mutations all at once: 17 mutations in viral proteins, including 8 changes in spike protein, the target for all of our vaccines. 2/
Why would a flurry of mutations suddenly emerge? The focus now is less on unique properties of #coronavirus and more on unique human hosts: patients with impaired immune systems who are chronically infected and unable to clear the virus. 3/ sciencemag.org/news/2020/12/u…