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October 10, 2020

Regeneron Antibodies in the News

We witnessed, in a very public way last week, the evaluation and treatment of a famous patient with Covid-19.  I previously mentioned Monoclonal Antibodies on August 26th in these blog posts.  But it seemed like a good time to review REGN-COV2, one of the two monoclonal antibody drugs that are early in their clinical trials in the US.  It was administered to President Trump early in his Covid-19 infection with a compassionate approval.  Read Below

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Early Results: 

REGN-COV2 is a mixture of two manufactured monoclonal antibodies to different binding sites on the SARS-CoV-2 virus spikes.  The Regeneron company currently has 3 clinical trials listed on governmenttrials.com: one in ambulatory patients, one in hospitalized patients, and one in individuals exposed to a Covid-19 patient.  There is limited data from these trials which only began several months ago.  All of the following information was presented at an investor meeting on Sept 29th for the first 275 patients enrolled in the ambulatory patient trial (Goal = 2000 volunteers).  

Trial participants all had positive virus tests and received a low dose, a high dose. or a placebo infusion   Patients' antibodies were also measured before treatment and results were analyzed based on whether they had already developed antibodies or not. Patients who received the REGN-COV2 antibody infusions reduced their virus loads and symptoms faster than placebo patients, and those who had not already produced their own antibodies had the greatest responses. Both doses were well tolerated.  Infusion reactions occurred in 4 patients - 2 on REGN-Covid2 and 2 on placebo - which is always a mystery to me.  

October 7, 2020

My Test Was Negative So I Didn't Wear a Mask

Last week there was a Super Spreader event at the White House and now guests have Covid-19.  The President's virus test was positive 5 days after the event. Everyone who attended the Rose Garden Party for Amy Coney Barrett had a rapid Covid-19 genetic virus test on arrival.   Guests were told that all of the tests were negative and therefore no one needed to wear masks.   At least 150 guests in the Rose Garden were photographed  - without social distancing or masks.  Everyone at the event should still have been socially distanced and wearing masks.  Read More about the test below.

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The White House uses the Abbott ID Now point of care molecular virus test.  The test was given FDA Emergency Use Authority for symptomatic patients with symptoms for < 7 days.  Articles I reviewed demonstrated, in some studies, that the test sensitivity wasn't high enough to pick up early cases of Covid-19, i.e. those samples that had low virus loads (up to 20% false negative tests).

A test like this is only helpful for rapidly testing symptomatic individuals, the results of the genetic test takes 5 minutes if positive and 13 minutes if negative. However, using this test to screen a population of asymptomatic individuals could mean missing many patients with early, transmissible SARS-CoV-2 as appeared to happen at the White House.

https://www.nytimes.com/live/2020/10/06/world/covid-coronavirus#fault-for-the-white-house-outbreak-lies-with-its-misguided-testing-strategy-health-experts-say   

 

October 3, 2020

What is Herd Immunity?

Viruses don't go away without vaccines. Measles, a highly contagious virus, was eradicated with vaccination, but occasionally pockets of infection do erupt in susceptible groups who refuse to be vaccinated.

Herd Immunity was recognized in the early 1900s, first by veterinarians, and then in humans.  When a high enough percentage of individuals in a community are exposed to a virus, the rate of transmission and infection slows down because there aren't enough susceptible people to pass along the virus.  Herd immunity needs approximately 70% of a community to either have been infected or vaccinated. 

The vaccines in the US must be at least 50% effective in order to get FDA approval.  If 100 patients are vaccinated 50 of them would develop immunity and protection.  If many patients don't accept vaccination, we can do another calculation:  If 100 people are offered a vaccine, and only 60% get vaccinated, and only 50% of them develop a strong immune response, only 30 patients of the original 100 patients would be counted in the development of herd immunity.  READ BELOW

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Dr.Tony Fauci, from NIAID/NIH, estimates that only 10% of the population in the US was infected so far.  Therefore vaccination is extremely important in the development of herd immunity to Covid-19.   

Bottom Line:  Develop a very safe vaccine, with high effectiveness (preferably 70%), and vaccinate as many people as possible.  Only then will our lives return to pre-pandemic freedom.  But we would still need to follow the Public Health Guidelines to control breakouts. 

 

September 30, 2020

A Temperature Check Entering a Restaurant?

New York City now has some charming outdoor restaurants on the sidewalk or street in front of their buildings.  This weekend people will be able to also eat inside these restaurants, which are limited to 25% occupancy.   In order to protect restaurant clients, temperature checks were recommended on each customer at the door. 

There have been recent articles and preliminary studies demonstrating that asymptomatic Covid-19 patients don't have fevers, but do have the same viral load in their noses, pharynx, and lungs as sick patients.  In several studies 30-40% of patients with positive virus tests are asymptomatic and don't have fevers.  These are the virus spreaders.  Therefore personal distancing and other possible public health measures are still recommended when congregating - social distance when possible, in good ventilation, and limit time spent when congregating inside.     

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September 26, 2020

Another Vaccine Enters a Phase 3 Trial

This week Johnson and Johnson began their Phase 3 vaccine trial in 60,000 volunteers.- joining the other 2 vaccines (Moderna, Pfizer).  It is a "viral vector" vaccine in which the gene for the SARS-CoV-2 virus spike is attached to an adenovirus which carries the gene into cells.  The gene then directs the cells to synthesize the coronavirus spike protein which stimulates an immune response in the volunteer.  This is a vaccine technique that J and J has used to make other vaccines, and their Ebola vaccine was approved this year in the UK.  The vaccine produced good antibody responses and there were minimal side effects in their phase 1/2 coronavirus  trial in almost 400 volunteers.  Only a single dose is needed and the vaccine is refrigerated, not frozen.  These are two major advantages of this vaccine. 

The vaccine protected Rhesus Macaque monkeys in a preclinical challenge trial - when they were vaccinated and then given the virus. 

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