COVID-19 FREQUENTLY ASKED QUESTIONS
Why are children less susceptible to COVID19 infection?
Fewer out door activities
Fewer ACE receptors in respiratory tract
Lower levels of cytokines
Immune protection from Coronavirus (CV) of common cold
Better function of T helper cell in children
Do children transmit less CV?
Pre-pubescent less chance of illness (<12 years)
Smaller lungs do not project droplets
Per Cent of COVID 19 patients asymptomatic?
Transmit 24-48 hrs before signs
Will asymptomatics have symptoms?
Symptomatics versus asymptomatics viral shedding?
Symptomatic patients 19 days
Asymptomatic patients 17 days
Per cent of COVID19 cases spread by asymptomatics?
How safe are current vaccines?
Rare side effects
CV vaccine effectiveness versus others?
Pediatric vaccines 90-99%
Astra Zeneca 70%
Can a patient be re-infected with COVID19?
Duration of vaccine protection?
Approximately 3 months (based upon current data)
COVID19 incubation period?
How long do patients shed virus?
median 22 days
Phase of COVID19 illness & viral shedding
Pre-symptomatic 11.5 days
Mildly symptomatic up to 10 days
Why CV vaccines need ultra cold storage?
Lipid nanoparticle unstable
Do masks work?
Prevents patients with CV from spreading virus via aerosol droplets
Limits exposure to droplets
Is reduced ambient temperature & RH enhance CV spread?
In colder weather people spend more time indoors
Reduced amount of H2O vapor per unit of air at low temperature, holds more virus
COVID19 better at 40-60% RH versus 20%
Dry respiratory tract less mucosal clearance of particles
Less sunlight leads to lower Vitamin D levels
Cold air causes vasoconstriction/microscopic tears
Dry air reduced RH, reduces size of aerosol droplets due to evaporation prolongs airborne spread * buy a humidifier
On what surfaces is CV most stable?
CV less stable on copper, copper nickel or brass
CV more stable on stainless steel, zinc, glass, ceramic, rubber
Greater survival=greater porosity
How long are COVID19 aerosols infectious?
At room temperature 68-72 F (20-22C), and 65% RH
an aerosol lasts approximately 3 hours
Do weather/climate determine where COVID19 occurs?
There is currently no conclusive data demonstrating
variations in climate effect COVID19 transmission.
However, countries with colder climates need stricter
public health measures.
What is a virus?
A bad piece of news wrapped in protein with a
sketchy set of engineering specifications.
The viral genetic material is its software.
Are genetic mutations always bad?
most point mutations are silent
if they confer a selective advantage, they will be selected
List the MOST important vaccines for children?
Haemophilus Influenzae B
Diptheria, Tetanus, Whooping cough (DTaP)
Measles, Mumps, Rubella (MMR), Hepatitis B
How effective are the typical childhood vaccines?
Typically these vaccines are 90-99% effective
How safe are the typical childhood vaccinations?
These vaccines are very safe. Millions of children receive
them every year.
No correlation exists between vaccines and autism.
Serious allergic reactions (anaphylaxis) 3.5/10 million
vaccinations. ISRs in10%, and fever in 2%.
What is the primary route of COVID19 transmission?
The primary means is via respiratory droplets
Large droplets settle quickly due to gravity
Smaller droplets evaporate to form aerosol particles
Low temperature/high RH favor droplets
High temperature/low RH favor aerosols
Extreme cold/humid scenarios droplets can reach 6M (19’22”)
Social distance of 1.4M (4’8”) blocks 95% droplet transmission
The Course of COVID19 Disease?
Incubation period 5-7 days
Initiation of symptoms day 1: viral load peaks (48hrs after symptoms)
Mild symptoms thru day 5-6 (hospitalization)
Severe illness day 10
Critical illness days 10-12 (ICU)
Antibodies day 12-14
What is the difference between a light microscope & EM?
Beam of electrons versus light
Electrons shorter wave length=higher resolution
LM resolution 0.05 uM vs EM resolution 0.02 nM
LM magnification 500-2000X versus EM 200000X
Scanning EM cost $1M
Compare genome sizes: Virus, Bacteria, Man
Virus measured in kB (10X3): 10-1600 genes: 16 proteins
Bacteria measured in Mb (10X6): 5000 genes: 1600 proteins
Man measured in Gb (10X9): 25,000 genes: 20,000 proteins
FDA granted emergency use authorization (EUA) for 100s diagnostic tests.
False negative 20-100%, earlier >FN rate
False positive 0%
Results: 1 hr-24 hrs
Viral Antigen Tests
Protein fragments, not NA
False negatives > PCR
False positive 0%
Results in minutes
Antibody Testing (serologic testing)
14 days PI IgG
False negatives 20% (0-30%)
Positive test # protective immunity/Or lack of contagiousness