As our most vulnerable begin to receive vaccine shots and the rest of us (im)patiently await our turn, I thought it would be a good time to read a little more about COVID-19, viruses and vaccines.
This is what I learned....Viruses have been around since the beginning of life on Earth. Actually, scientists believe they were here even before life. There's evidence that a virus could have influenced the beginnings of that very first organism from which all plant and animal life has descended. I was astounded to learn from a recent National Geographic article that the development of the placenta started with a virus. If it was not for a virus,, we could still be incubating our babies in eggs like chickens.
Viruses are not considered a living thing. They are transport vessels for DNA and RNA and can only survive and replicate within a host cell. Some viruses just break in and take up residence, maybe remodel a bit but don't destroy the house. Others throw a house party and use the host's 3D printer to replicate themselves so many times that the house, their host cell, explodes sending thousands of copies to find new host cells to invade.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of seven types of coronaviruses that can be found in humans. Four of the subtypes are relatively harmless but the other three are known to cause severe illness with SARS-CoV-2 being the virus which causes the disease COVID-19. Scientists are still trying to find out how, where and when SARS-CoV-2 originated but varying coronaviruses have been around since the 1960s.
Not all those infected by SARS-CoV-2 will develop COVID-19. It is believed that at least one third of those infected are asymptomatic meaning they have been infected but have not developed symptoms of COVID-19. It is possible that some of these asymptomatic cases have underlying signs of COVID-19 disease but we are unsure what this means longterm. The virus replicates and kills host cells similarly in all cases of infection. Copies of the virus are then released through bodily fluids and waste in a process called viral shedding. All those infected will have some degree of viral shedding with asymptomatic cases usually producing the least amount.
The primary mode of transmission of SARS-CoV-2 is through respiratory droplets. If these droplets come into contact with the mucous membranes of our eyes, nose, or mouth or breaks in your skin you can become infected. Once the virus enters the body, white blood cells begin swallowing up the invading virus germs, leaving behind bits of them called antigens. Other white blood cells produce antibodies that recognize and attack these virus bits. We also have memory cells which take a selfie with the antigens so they'll be able to recognize them quickly the next time they come to visit. This memory produced by infection is how we develop natural immunity. Eventually that picture will fade and we will lose much of our natural immunity but we do not yet know how long that takes with SARS-CoV-2.
Vaccines send a text message with a virus selfie to your antibodies. They use varying methods to allow your antibodies to recognize virus antigens. When you come into contact with SARS-CoV-2 your body will already know what it looks like and can more quickly and efficiently attack and destroy it. Historically, vaccines have used weakened virus or parts of a virus in order to achieve this.
Decades of research and new understanding of DNA and mRNA has allowed scientists to develop a different kind of vaccine called mRNA vaccine. Our bodies use messenger RNA (mRNA) to send messages in order to create new proteins based on that message. The mRNA vaccines introduce modified mRNA into your body that carries a selfie of the SARS-CoV-2 virus. This allows for production of proteins that look just like it. Essentially, it delivers a selfie that can be used to produce multiple 3D models of the virus that your immune system can use as a practice run in preparation for the real thing. Since its only made in the image of the virus and not actually the real thing, you will have the benefit of future recognition without the deleterious effects of COVID-19.
These mRNA vaccines are capable of providing a stronger immunity than natural immunity which is why it is recommended that those who were previously infected get vaccinated. Currently, there's no evidence that these vaccines will actually prevent infection but they do prevent COVID-19 in the vast majority, most significantly preventing hospitalization and death associated with severe disease. Similar to asymptomatic cases, vaccinated persons who have become infected may still be able to infect others but at a much lower rate due to less viral shedding.
Like other viruses, SARS-CoV-2 mutates on a regular basis. It is actually mutating at half the rate as influenza and one-quarter the rate of HIV. Most variants (the term used to describe the mutated version of the strain) are mostly unremarkable. Unfortunately, sometimes there are a significant number of mutations that occur over a short period of time that can lead to the virus developing an evolutionary edge such as increased transmissibility or an improved ability to avoid antibodies. They now look a little different from their original selfie which makes it more difficult for your antibodies to recognize them. As mutations continue, it will be necessary to adjust the vaccines to send in updated selfies via booster shots. Your annual flu vaccine is an example of booster shots to help build immunity for influenza variants.
No matter if you receive one of the new mRNA vaccines or a traditional one, the bottom line is to make sure you get one. The more this virus is allowed to spread the more opportunity it will have to mutate and gain evolutionary advantages. If you are unsure about the safety and efficacy of a vaccine in your case, discuss it with a doctor. Some vaccines may end up being more appropriate for certain populations than others. Similar to other pharmaceuticals, they are made slightly different but achieve the same result. They are designed to support our bodies' systems by promoting or inhibiting actions in order to prevent disease. Also like most medicines, they have side effects that you should make yourself aware of but keep in mind that all vaccines approved by regulating authorities have been tested and deemed safe for the general public.
Get a shot! The life you save may be your own.
Physical Activity after COVID-19
I recently read an article in a popular magazine about the importance of stopping exercise once you test positive for SARS-CoV-2 or develop COVID-19. This is sound advice but it did not mention anything about how to return to activity once you were feeling better. I decided to take a deep dive into to find out more. I found two evidence based articles that were helpful in providing simple guidance. We are still learning about the short term and long term effects of infection and COVID-19 on the body so it's important to take precautions when resuming activities. Wait a couple weeks after either a positive test (asymptomatic) or after your symptoms have resolved before beginning any type of exercise. Start with light activity and progress slowly over at least four weeks while taking note of any increased fatigue or return of symptoms. I have included links to both articles as well as charts from the articles that I found helpful.
Salman David, Vishnubala Dane, Le Feuvre Peter, Beaney Thomas, Korgaonkar Jonathan, MajeedAzeem et al. Returning to physical activity after covid-19 BMJ 2021; 372 :m4721. https://doi.org/10.1136/bmj.m4721
Metzl, J.D., McElheny, K., Robinson, J.N. et al. Considerations for Return to Exercise Following Mild-to-Moderate COVID-19 in the Recreational Athlete. HSS Jrnl 16, 102–107 (2020). https://doi.org/10.1007/s11420-020-09777-1
How are you feeling so far this year? Any less stressed than last year? more stressed? Sometimes it can be good just to check in on those stress levels and see how you're fairing. Take this short quiz and if you score a little higher than you like on the stress scale then consider trying some yoga, mindfulness activities, breathing techniques or other management strategies to see if you can make a positive change. Check your progress monthly to see if you're headed in the right direction or if you may need a bit extra help managing.