Covid Basics: The Science and What to Know Before You Travel — Part 1

Ted Fahy and Priscilla Taylor are traveling with us to Chiapas in February 2022. We’ve been having back and forth conversations about traveling as safely as possible during COVID. Ted is a retired pediatric physician and Priscilla is a retired pediatric nurse practitioner. I invited them to write an occasional commentary about COVID, concentrating on its relevance to travel.

Because Ted and Priscilla can decipher COVID in basic, easy-to-understand lay person terms, I thought what they say might be helpful to Oaxaca Cultural Navigator clients and readers. Perhaps, this will also be informative for others who are considering international or national travel, too.

Today’s newsletter gives you background for Ted and Priscilla. We are also starting with the basics — What are the differences between viruses and bacteria.

About Edward Fahy, MD and Priscilla Taylor, PNP

We are Ted, retired Pediatrician who is still an active Fellow of the American Academy of Pediatrics, and Priscilla, retired Pediatric Nurse Practitioner.  Between us we have 85 years of clinical training and experience.  Pediatrics has always been a medical discipline primarily concerned with infectious disease.  We both were born when polio was rampant and rubella (German Measles) caused countless cases of mental retardation, hearing loss, heart defects and blindness – and when a bacterium called H. influenzae (NOT the same as the virus Influenza) killed thousands of kids per year in the U.S.  Ted’s very 1st patient in 1975 was an elderly woman who lived through the Influenza pandemic in Philadelphia in 1919.  She vividly recalled how a family in the brownstone next to hers all died in one night during that pandemic.  

Through long experience we are extremely familiar with infections.  Our goal is to explain the basics of epidemic disease so that you will have a context within which you can better evaluate information about COVID and better understand why at times there is so much confusion and lack of clarity.


You can’t talk about epidemic disease without discussing three things: Biology, numbers, and understanding causation.  All three can be intimidating and/or boring.  We’ll do our best to make them interesting.

Viruses and Bacteria

These are profoundly different – and the differences mean everything.

Bacteria – are alive in every sense of that word.  They need food for energy (usually a sugar) and will reproduce every 20-40 minutes.  They are very genetically complex, with 4,000 – 5,000 genes. They have many hundreds of chemical reactions (“metabolism”).  They are relatively big – very easy to see with an ordinary microscope.  

Most importantly, it’s possible to treat and kill bacteria after they have infected the body because they are killed by antibiotics, which disrupt their chemical pathways.

The simplest example is penicillin, which kills streptococcus (as in strep throat).   Penicillin is taken by the strep and put in its cell wall….but that creates a weak wall structure and the bacterium literally explodes!!!!

Viruses – are not alive at all.  They don’t use food.  They are genetically extremely simple.  SARS-Cov-2 (today’s Covid) has about 31 genes.  Outside the body they are inert, do not duplicate, and have NO active chemical reactions.  They are incredibly tiny – impossible to see with a standard microscope.  They have a very different mechanism of actionfrom bacteria.  Much like magnets, they attach to a cell, squirt their genes into it, and hijack the cell’s chemistry, using very few chemical reactions to make copies of themselves. 

Here is a link to a description of exactly how COVID attaches to and inserts its RNA gets into our cells: or click on the video below

Viruses are literally self-copying xerox machines – so they produce new viral particles incredibly rapidly.   The numbers for viruses are staggering – almost incomprehensible.  If you take a nasal swab of someone with influenza, a single swab can contain 800 million viral particles. One single swab.  

Worse – You can’t “kill” them because they aren’t alive. This means that antibiotics don’t work.  Yes, there are some instances of antiviral agents, but none of them actually kill viruses.  They only inhibit the self-copying process or enable white blood cells to identify and destroy the viruses.  Once a virus infects a person, the main medical goal is to support of the body’s own defenses.  The primary approach to viral infection is immunization: Prevention by priming the immune system to recognize the virus ahead of time.

Next time:  Our immune system – White blood cells, antibodies, and how they work together to eliminate infectious organisms.

Norma’s Note: We don’t have a regular publishing schedule for Ted and Priscilla’s newsletter. We are hoping this short series will inform you over the next few weeks, in between our commentary about Oaxaca life and culture.

Notice: This is not intended to substitute for consultation with a medical professional. We are not providing medical advice or diagnosis. This is for general information purposes only. For all medical questions related to vaccines and COVID-19, please consult your medical professional.

At Oaxaca Cultural Navigator LLC, we require all travelers with us to be fully vaccinated. This definition as of December 25, 2021, means two vaccines and a booster. Flu vaccines are strongly recommended. We also ask that our travelers bring and wear N95 or KN95 — which are demonstrated to offer maximum protection.

FYI: We have three vacancies for our March 8-16 study tour to Chiapas. Please contact Norma if you are interested.

And, as always, thank you for reading.

2 responses to “Covid Basics: The Science and What to Know Before You Travel — Part 1