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September 29, 2021

Masks Do Reduce Covid Spread

A recent CDC Morbidity and Mortality Weekly Review article was discussed on a podcast I listen to and I thought the information was worth sharing.  St. Louis University instituted a program to reduce Covid spread among students during in-person instruction.  These measures included physical distancing. mask use, vaccination, contact tracing, case investigation and quarantine.  The University also instituted a modified quarantine regimen which depended on whether students were masked or unmasked during contact with an infected student.  The study took place from January through May 2021 so the effects of the delta variant weren't captured during the study.

There were 265 students who developed Covid-19, and 375 students who were named as close contacts to the infected student. Close contact exposures were defined as a single exposure in which the two persons were within 6 feet of each other for >15 minutes during a 24 hour period.  The number of exposures were then calculated for each close contact.  Mask use was calculated for each exposure - if either the patient or the contact were unmasked, it was considered an unmasked exposure.  Only unvaccinated close contacts with unmasked exposure had to quarantine, the rest were asked to monitor their symptoms.  Eighty-nine % of students were unvaccinated and 70% of the students lived on-campus.   See Results Below


Only 7.7% of subjects developed Covid-19 if they had masked exposures, and 32.4% developed Covid-19 if their exposures were unmasked - a statistically significant difference.  There was no information provided about the types of masks worn, which means that fabric masks and surgical masks were probably the predominant types worn based on the types of masks seen most commonly.  Surveillance testing was randomly done on approximately 10% of on-campus students. These types of studies are difficult to conduct but this one, before the spread of delta, provides a rationale for universal mask wearing.  

September 25, 2021

3rd Doses of the Pfizer Covid Vaccine

It is really difficult to collect real world data to clarify whether there are waning vaccine levels and decreasing vaccine efficacy or whether some increase in cases among the fully vaccinated people over 65 are due to the Delta Variant.  Pfizer presented some data on subjects from their Phases 1 and 3 Clinical trials.  After the trial unblinding the placebo group was able to request a vaccination and the two groups can be compared based on the length of time since each group was vaccinated.  All of the volunteers analyzed were 18-55 years old, so the data they wanted to assess is not available for the oldest people.  But both the FDA and CDC advisory boards said there was enough suggestive data that people older than 65 (including those in long term care facilities) had some decrease in vaccine efficacy and were vaccinated very early in the vaccine rollout in Dec, Jan, Feb.  There were excellent responses to the 3rd dose and adverse effects were less than following dose 2. 

Some very experienced scientists think this may be one of the 3 dose vaccines, with dose 3 spaced at least 6 months following dose 2.  It would be wonderful if the duration of protection is years, as is seen in the current non-Covid 3 dose vaccines!  I watched both the all day FDA meeting, and the two day CDC Meeting and feel as if the advisors very carefully assessed the scientific data re: vaccine efficacy and analyzed the safety data from those who received 3rd doses already (in trials or due to immunodeficiency).  The reactogenic symptoms following the 3rd dose were actually a little less than the 2nd dose symptoms, and no new "safety signals" were found.  The mRNA vaccines can cause myocarditis-pericarditis, but it occurs primarily in young males.  It is very rare, very mild, and resolves quickly in the majority of the vaccinated.  CDC link summarizes the current  recommendations (note the "should" and "may" language: See Below



I think that one of the major observations made during these two meetings was as follows:  The pandemic will not change substantially because of the 3rd doses that will be given. The current vaccines are still really effective, especially preventing severe infections, hospitalizations, and death. In places with a low vaccination rate, the stress on the health care system due to unvaccinated ICU patients is now affecting the patients who need non-Covid care and deaths of these people are increasing.   The only way for the pandemic to change is to increase the number of people who get vaccinated with the standard 2 dose regimens NOW.  If you have a chance to change a mind, please discuss the need for a vaccine whenever and wherever you can.  I will never understand the people who don't want to put "unknown vaccine ingredients" into their body, but have no problem taking doses of Ivermectin meant for cows and horses (poisonous), putting hydrogen peroxide in vaporizers (a toxin for lungs when inhaled) or swallowing betadine (Toxic).   


September 22, 2021

Pfizer Vaccine for Children 5 to 11Years

This week Pfizer announced that they will be submitting an EUA request to the FDA for their vaccine for children ages 5 to 11.  There was a 240% increase in the number of Covid cases in children since July when the delta variant increased dramatically in the US.  Data from the Phase 3 clinical trial will be submitted and hopefully the FDA and CDC with their advisory boards will approve the efficacy and safety by the end of October.  Many parents were very concerned about these children going back to school and already there are many schools who had to close down classrooms because of Covid infections.

Different doses of vaccine need to be tested in children, and the immune response, as measured by antibody studies must be as good as the results in a control group.  For this study 2268 participants who were 5-11 years old were given two 10ug doses of vaccine 21 days apart.   Antibody levels measured 1 month after the second dose were comparable to those measured in the 16-25 year old control group who received two 30 ug doses 1 month apart in the Pfizer adult study. In addition to assessment of the immune response the vaccine must have no significant safety concerns.  Pfizer reports that the vaccine was "safe, well tolerated and showed robust neutralizing antibody responses."    See Below


Pfizer will submit all of their data from the 5-11 year old children and the FDA will review the immunologic and safety data for each participant.  The FDA will present the information to their scientific advisory groups for discussion and hopefully approval.  The CDC will then review the same data and present it to their advisory board.  Only then will the vaccine be released to children in this age group. 


September 18, 2021

FDA Meeting Re: Pfizer Booster

The scientific advisory committee to the FDA listened to a full day of presentations about the Pfizer vaccine - its vaccine efficacy against infection and its safety.  Data was presented by a scientist from the UK, scientists from Israel, the CDC, FDA, and Pfizer.  The vaccine is still effective against severe infections, hospitalizations, and deaths.  By the end of the day agreement was reached that there was some data demonstrating that vaccine efficacy was waning in older patients with exposure to the delta variant.  When given a 3rd dose their relevant Covid antibodies increased 10-fold. In each of these studies it was still unclear whether vaccine efficacy was waning or the arrival of the delta variant, or a combination of both.   

Safety information was also reviewed in these presentations, and the advisory committee members didn't think they had enough data yet on third boosters in the younger groups of males who are at increased risk of developing myocarditis-pericarditis.  There were no new safety issues, and even though the heart side effect was rare and mild, the committee recommended that the 3rd dose be held until there is more data. Other side effects were very similar to those associated with 2nd doses.  


The original question to be answered was whether a 3rd dose of the Pfizer vaccine should be given 6 months after dose 2 to people 16 years or older.  That vote didn't pass.  But each member of the committee felt that the 3rd dose should be given to 1.) fully vaccinated people 65+ years old, at least 6 months after dose 2.  2.)  People who were at high risk because of their occupational exposures. This proposal passed unanimously.  Meanwhile more data will be accumulated and analyzed - both to see if the vaccine efficacy is dropping and to make sure that 3rd doses are safe in younger people.  That proposal passed unanimously.

It is so interesting to watch a full day of scientific data presentations and to learn from experts on vaccine efficacy and safety.  I watch every one of these advisory committee meetings and will get my 3rd dose (because I'm 65+) as soon as the CDC advisory committee meets next week to review the data and approve the FDA decision.


September 15, 2021

Covid Sniffer Dogs Working in Miami Airport

The dogs identification of coronavirus is almost instantaneous. Sniffer Dogs have 50 times as many receptors in their nose as humans and dogs can be trained to recognize drugs, explosives, many other items and now coronavirus infections.  I wrote about 10  Covid sniffer dogs in Helsinki in October 2020 (http://www.paperandthreads.com/2020/10/sniffer_covid19_dogs.php) and learned that if they were already trained with other scents, it took only a short time to train them to recognize Covid infections.  Then there wasn't any other news that I saw about the use of sniffer dogs since then.  Now 2 purebred and 2 "pound puppies" were trained and will be used in a 2 month pilot study in the Miami Airport, the first in the US.  In the beginning they are identifying infected airport and airline employees as they report to work.  Then they will be moved to other areas in the airport to check passengers.  The passenger dog testing will be voluntary. 

Cobra and One Betta (a Belgian Malinois and a Dutch Shepherd) spend their shift sniffing employees' face masks to detect coronavirus in sweat, breath, and scents that develop in an infected human body.  If the dog detects the virus, a rapid virus test is done for confirmation. Florida International University researchers did a double blind trial with the dogs and found that One Betta's accuracy rate was 98.1% and Cobra's was 99.4% accurate.   


Sniffer dog screening, when certified, could reduce the time needed to screen passengers before flights. The Miami Airport is one of the busiest in the US.so the pilot program should have lots of opportunity to collect more data on the sensitivity and specificity of the sniffer dogs during the study.  The dogs have a favorite ball they like to play with, and when they see it they know they will go to work and then get their playtime!

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