October 21, 2020

Pregnancy and Covid-19

There is still a need for further clinical studies on the effect of SARS-CoV-2 on pregnancy.  In general it is recommended that women follow all the public health safety measures to prevent getting Covid-19 at all during pregnancy.  The studies show that Covid-19 is slightly more severe during pregnancy and there is a higher incidence of ventilators.  But there is no increase in mortality.  There is only very rare transmission of the virus to the babies, and it is not clear whether that occurred prior to or after delivery.  The babies rarely have problems due to the virus and it is not transmitted in breast milk. Mothers who want to breast feed are recommended to perform strict hand washing and mask wearing while feeding the babies. Read Below. 

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Doctors at NYU Hospitals in New York studied 149 mother-child dyads and it is one of the largest studies published to date.  Forty% of the mothers were asymptomatic and picked up on screening.  15% of the symptomatic mothers required some type of respiratory support.  Symptomatic mothers had a significant increase in preterm births ( 16% vs 3%  P=0.02).  Only 1 newborn was + for SARS-CoV-2 and that was believed to have happened post-partum.  There were 3 sets of twins, 3 still births, and 1 post-natal death. (Publication in Pediatrics journal this month).

October 17, 2020

Sniffer Covid-19 Dogs

Sniffer Dogs Make the News:

Humans have 6 million receptors for smell in their nose, dogs have 300 million receptors, making them very good at detecting volatile organic compounds made in our bodies.   They have been trained to detect malaria infections, bacterial and viral infections, bombs, contraband in luggage, and some types of cancer.  Several weeks ago the New Your Times published a story about sniffer dogs being trained to detect infected covid-19 patients in the Helsinki airport.  Read More Below.

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They trained 16 dogs and expect to have 10 in the airport by the end of November.  Six dogs weren't able to work in the noisy environment. 

The dogs can detect Covid-19 infections in less than 1 minute and can be used with a trainer to screen travelers in lines in airports.    The dogs can detect the Covid-19 infection in asymptomatic people, and test sensitivity is as high as 85 to near 100%, with equally high specificity. Dogs who have been trained for other scents can learn to detect Covid-19 infections in 1 week,   If they have never been trained with other scents, it takes significantly longer. 

Similar trials are being conducted in the UK, France, Germany, Lebanon and the US (at U Penn Vet School).   Dogs are being trained to sniff saliva, nasopharyngeal secretions, sweat, and urine.  In Helsinki passengers wipe their necks with a wipe and then put the wipe in a cup for testing.  

October 14, 2020

Test-Track-Isolate to Control Coronavirus

Test-Track-Isolate:  When New York State was able to shut down for weeks last Spring to control the surge of Covid-19, the number of cases dropped progressively.  The curve of daily new positive cases looked like a really tall mountain with a gradual decline to a stable low baseline.  The state then reopened in phases, very slowly, and by region, and the cases and deaths continued to decline.  Each day the state was testing 60,000 -100,000 people, and recently it has been more than 100,000 tests per day - with 1% daily positive cases or less in New York State and New York City for several months.   Read More Below.

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In the last week hot spots developed and were detected by the daily testing.  Most of the infections followed large gatherings with limited to no mask wearing.  The Dept of Health was able to pinpoint the clusters to specific zip codes, in Brooklyn, Queens and several surrounding counties.  The areas were divided into yellow - orange - and red zones by the number of new cases, and each of the zones had new imposed limits placed on the people.  I walk in my neighborhood in Manhattan early every morning and almost everyone is wearing masks - including even the youngest toddlers in strollers.  Everyone wants to prevent a surge in the virus infections and deaths this Fall.

 

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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September 23, 2020

Are There Covid-19 Reinfections?

Within the last weeks Covid-19 reinfections were reported in 4 patients, separated in time from their first episode.  Sometimes patients continue to have a positive molecular virus test after their Covid-19 infection, but the PCR test is able to measure remaining dead virus after recovery. RNA viruses mutate slowly, usually in unimportant portions of the virus.  The ability to sequence the RNA allows scientists to detect mutations - and that is how they determined that NYC was infected with a European strain of SARS-CoV-2, not the Wuhan strain.  The European strain was infecting communities in NYC long before there was any control of the planes arriving from Europe or even China. 

I was surprised that in the 4 patients with recurrent disease (one each from China, Belgium, Netherlands, and Nevada), scientists were able to compare the SARS-CoV-2 virus that was isolated from both their first and second positive SARS-CoV-2 virus samples.  There were different mutations present when the rwo samples were compared, thus demonstrating that these were 2 separate infections in each patient.  It is not clear how many cases of reinfection will be reported, virus samples from each episode must be available for testing.  These cases were each reported online, not in published scientific papers that I could find. 

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Shirley Parker Levine
New York City

October 2020

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