Respirator masks (tight fitting) lower risk of infection by 83%. Other masks are not as effective.

Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021 Weekly / February 11, 2022 / 71(6);212–216

On February 4, 2022, this report was posted online as an MMWR Early Release.

Kristin L. Andrejko1,2,*; Jake M. Pry, PhD2,*; Jennifer F. Myers, MPH2; Nozomi Fukui2; Jennifer L. DeGuzman, MPH2; John Openshaw, MD2; James P. Watt, MD2; Joseph A. Lewnard, PhD1,3,4; Seema Jain, MD2; California COVID-19 Case-Control Study Team (View author affiliations)

“Consistent use of a face mask or respirator in indoor public settings was associated with lower odds of a positive SARS-CoV-2 test result (adjusted odds ratio = 0.44). Use of respirators with higher filtration capacity was associated with the most protection, compared with no mask use.”

Study: of 1.2 million fully vaccinated people with no risk factors, *ZERO* had a severe COVID infection (Dec 2020-Oct 2021)

The study published on the website:

Risk Factors for Severe COVID-19 Outcomes Among Persons Aged ≥18 Years Who Completed a Primary COVID-19 Vaccination Series — 465 Health Care Facilities, United States, December 2020–October 2021

says the following:

Among 1,228,664 persons who completed primary vaccination during December 2020–October 2021, severe COVID-19–associated outcomes (0.015%) or death (0.0033%) were rare. Risk factors for severe outcomes included age ≥65 years, immunosuppressed, and six other underlying conditions. All persons with severe outcomes had at least one risk factor; 78% of persons who died had at least four.

MMWR Morb Mortal Wkly Rep 2022;71:19–25. DOI:

So, if I’m reading this correctly, there were ZERO severe COVID-19 associated outcomes for fully vaccinated people with no risk factors (mostly before delta, mostly before boosters). Zero! Isn’t this a huge deal? Shouldn’t this be headlining newspapers? I don’t understand why it’s not in the news. And now with Omicron (milder infection) and boosters (better protection), current protection should be even better.

In this study, a severe COVID-19 outcomes is defined as:

– Diagnosis of acute respiratory failure
– Need for non-invasive ventilation (a tight fitting oxygen mask)
– ICU admission
– Death

Interestingly, tracheal intubation isn’t listed here, but I guess that’s associated with the ICU.

Epidemiology of COVID-19 Spreading via Breathing, Coughing, Sneezing, Singing, & Talking in Various Settings

This just one of the fascinating examples in this article of how epidemiologists tracked down very specific examples of COVID-19 spread in different situations:

Some really great shoe-leather epidemiology demonstrated clearly the effect of a single asymptomatic carrier in a restaurant environment (see below). The infected person (A1) sat at a table and had dinner with 9 friends. Dinner took about 1 to 1.5 hours. During this meal, the asymptomatic carrier released low-levels of virus into the air from their breathing. Airflow (from the restaurant’s various airflow vents) was from right to left. Approximately 50% of the people at the infected person’s table became sick over the next 7 days. 75% of the people on the adjacent downwind table became infected. And even 2 of the 7 people on the upwind table were infected (believed to happen by turbulent airflow). No one at tables E or F became infected, they were out of the main airflow from the air conditioner on the right to the exhaust fan on the left of the room. (Ref)



Supersonic Retro Propulsion for Trips to Mars

Apparently, the decision has been made at NASA that supersonic heavy load parachutes just won’t work.  So instead, a rocket to Mars will enter the Mars atmosphere at supersonic speeds using the shockwave from a blasting “retro” rocket to plow through the air instead of the old fashioned heat shield  (“retro” here meaning opposite the direction of travel, not old fashioned)

Given this decision it’s interesting that SpaceX’s last booster reentry intentionally started it’s reentry burn high to simulate supersonic reentry burn conditions in the Mars atmosphere.    And NASA mobilized special thermal cameras to record this experiment (that otherwise would’ve cost NASA hundreds of millions to test/simulate)

Also see:

Development of Supersonic Retro-Propulsion for Future Mars Entry, Descent, and Landing Systems (PDF)

SupersonicRetroPropulsionAnd a video at:

Supersonic Retropropulsion (wind tunnel) Test, Mach 4.6 Schlieren Video (youtube)

I like saying “Supersonic Retro-Propulsion”

The sequester will set back medical research for a generation.

According to the former director of the NIH, Dr. Elias Zerhouni (in the Washington Post):

The NIH is facing an 8.2 percent across-the-board cut in future years (5.3 percent for 2013).

The most impacted are the young, new investigator scientists, who are coming into science, and will now abandon the field of science. There will be a generational gap created.