Medical Bits – Vol. 1.8: Your Health – Viruses and You
Why should you continue reading the next few pages? Because you will likely develop at least a few viral infections every year of your life. Because viruses are part of you and your genetic content. Because life without viruses would be impossible and… because it is a wonderful story and that, is what fills our lives!
Few humans need to be reminded that our species is not at the center of the Universe, (even if your physicists friends can demonstrate that since our Cosmos continues to expand in every single direction at the same speed, any point in the Universe is technically at “the center”). We have known about different biological entities for centuries. In 1798, Edward Jenner published his ”Inquiry into the Variolae Vaccinae” (Cow Pox) in which he described the protective effect of cowpox against smallpox, launching forward a new field of immunology. Smallpox had a mortality of 10-20%, which evaporated thanks to Jenner’s observations. The contributions of Edward Jenner and Louis Pasteur and the development of “vaccines” that they promoted along with the sanitation measures of the late 19th and early 20th century have been the most important factors responsible for the leap in human longevity in the past 200 years.
As you know, the edifice of science is built slowly and through the painstaking work of committed researchers with steps forward and a few backwards, until slowly the pieces of the puzzle are filled in and the full panorama appears, leading to further questions and deeper understanding.
It is difficult to overstate the importance of Louis Pasteur and his restless scientific journey, despite suffering a right cerebral hemorrhage at age 45 and at the prime of his career, which left him with left-sided hemiplegia for the rest of his life. As was usual at the time, he was treated with the application of medicinal leeches behind his ears and despite the initial concerns for his life, most of his important contributions to science were completed by a hemiplegic Pasteur, who along with Einstein have been the most celebrated scientists of human history.
Jenner (smallpox vaccine) and Pasteur (rabies and anthrax vaccines) could not know of the existence of viruses as they are too small to be seen through light microscopy, but careful application of observation and epidemiologic information allowed them to infer cause-effect relationships and develop their vaccines. That keen observation contributed to numerous chemical and biological discoveries, leading to the definitive demolition of the prevailing notions of “spontaneous generation” of bacteria (1858) and infection control in maternities where puerperal fever (post-partum infection) and sepsis had a terrible mortality. The Hungarian physician Ignaz Semmelweis enthusiastically promoted hand washing with chlorinated lime solutions while working in the Vienna General Hospital’s first obstetrical clinic, before Pasteur’s publications of his “Germ theory”. He documented that the doctors’ wards had three times the mortality of midwives wards, and published his observations in 1847. Colleagues mocked and resisted his infection control measures, eventually claiming that he was deranged and infamously, committed him to a psychiatric asylum where he was beaten by guards and ironically died septic, 14 days later at age 47 from a wound inflicted upon admission.
In 1881, in honor of Jenner, Louis Pasteur proposed that the term vaccination should be extended to cover the protective inoculations in development.
Biologists and researchers knew about the existence of microbes smaller than bacteria, and vaccines based on epidemiologic information were slowly developed. Viral epidemics were also ameliorated through vector control (think about the completion of the Panama Canal in 1914 after improved control of mosquitoes and the Yellow Fever epidemics they spawned). Due to their small size, viruses remained elusive until the early 20th century. They could finally be visualized after the discovery and deployment of Electron Microscopy in 1931. The new tools and application of the Scientific Method revolutionized our understanding of disease and biology through the past century.
Thanks to the labors of earlier generations, it is now much easier to categorize diseases and understand “etiology” (cause and effect).
But, before we discuss different living organisms, most of you may wonder, what is life?
Is it the “flow of energy, matter and information”? “Is it a complex chemical system able to evolve and replicate”? There are numerous definitions of LIFE, but according to NASA’s exobiology panel, “life is a self-sustaining chemical system capable of undergoing Darwinian evolution”. Through the past 4 billion-years, “life” likely emerged millions of times and in different forms! Remember that more than 99% of all species that ever existed on planet Earth are now extinct! Of course, one day we may follow the same fate…Evolution never stops. The only constant of life, any life, is change. Thus, we now know of numerous biologic entities, some, able to cause disease, but all essential for life on our planet as we know it. Imagine that without bacteria, fermentation and the libations you enjoy some evenings as you read this page, would not be possible. And without certain yeast and fungi, the bread that calms your appetite and the yogurt that has nourished your mornings would be unimaginable. Thus, all creatures have a place in our tiny corner of the Cosmos.
The main types of micro-organisms belong to families of bacteria, parasites, fungi, prions and viruses. There are several sub-classifications within each family, some with hundreds of members!
Let’s discuss Respiratory Viruses.
Viruses are the most abundant biological entities on the planet. They are present in our surroundings, oceans, soil and in every living creature and pre-date the emergence of complex cells. They are the most successful parasites of all domains of life and without them, the evolution of species would very difficult to fully understand.
It is estimated that retroviruses (type of virus that is able to insert its genome into the nuclear DNA of the invaded host cell, changing the genetic material of that cell) contributed more than half of our genomic sequences historically and 8-10% of our current genome can be traced back to ancient and extinct retroviruses.
Epidemics began when humans aggregated in communities in the early Neolithic period. Most viruses, despite our fears, are beneficial and have driven evolution by transferring genes across and within species.
As we think about respiratory viruses, Influenza is the first one to come to mind yet, most cases of Influenza-like-illness (ILI) are not caused by Influenza, but rather other viruses (rhino, corona, adeno, para-influenza viruses, human respiratory syncytial virus) or less commonly bacteria such as mycoplasma, chlamydia or streptococcus pneumoniae. No wonder we claim that the vaccine is ineffective!
Influenza is a single stranded, segmented, RNA virus that has the singular ability to re-assemble its RNA segments leading to different strains and minor (called drifts) or major changes (called shifts) and in turn to different viruses annually or in mid-season. It is for this reason that the Influenza vaccine needs to be updated annually.
The main types of Influenza Vaccine are Inactivated and Live-attenuated. Within the Inactivated group, there are trivalent and quadrivalent vaccines as well and standard and regular-dose vaccines.
All Humans older than 6-months old are recommended to obtain Influenza vaccine annually. Individuals older than 65 are recommended the high dose inactivated trivalent vaccine (HD), which provides a higher amount of antigen (60 ucg) against three different strains. The standard quadrivalent vaccine has 15 ucg of HA and NA antigen per strain. A new recombinant quadrivalent vaccine has 45 ucg of HA antigen per strain. While the HD vaccine has been proven to be more protective than the standard dose in the elderly, there have been no clinical trials to compare the efficacy of the new quadrivalent recombinant vaccine, but it is anticipated to be quite similar to the HD and protective against an additional strain.
The live-attenuated vaccine is not recommended for patients with immunocompromise, in pregnancy and in individuals with respiratory conditions. While the influenza vaccine is not fully protective, and its efficacy varies from season to season according to the concordance with the prevailing circulating influenza strain, disease is likely to be milder and therefore wise to get immunized!
Our lives begin to end the day we become silent about things that matter.
Medical Conditions: Influenza
You all know the classic symptoms of the “FLU” which were clearly described by Hippocrates over 2,400 years ago: High fevers, runny nose, sore throat, muscle pains, headache, coughing and fatigue that usually ensue rapidly after infection. In children, diarrhea and vomiting may be present but less commonly in adults. Severe disease is possible and depends on the virulence (aggressiveness) of the prevailing strain and host factors. Influenza killed vast numbers of the indigenous population of the Americas, who had no prior exposure, in deadly outbreaks that began shortly after the arrival of the “Conquistadores”. And you may recall the devastating Influenza Pandemics of the 20th century: Spanish Influenza of 1918 (40-50 million deaths), the Asian Influenza of 1957 (2 million deaths) and the Hong Kong Influenza of 1968 (1 million deaths). There are 4 types of Influenza viruses: Types A, B, C and D, but the last two rarely cause human disease and different strains within each type. It spreads around the world in yearly outbreaks mainly in winter months in the Northern and Southern hemispheres, while around the tropics outbreaks may occur at any time of the year. It is estimated that worldwide, 3 to 5 million people suffer severe disease and 300-500.000 die. Since the virus mutates and evolves rapidly, the vaccine must be updated annually. And you should make plans to be vaccinated, ideally before November!
Debunking Myths: Q&A
Myth: The FLU vaccine caused me to catch the “flu” and I became ill”!
Not true!!! There is no evidence that this is true or that it could possibly have any biologic foundation. The vaccine components are two proteins / antigens that are present in the surface of the Influenza virus, Hemaglutinin and Neuraminidase. No injectable influenza vaccine has a complete virus able to replicate and cause disease. Some people may develop a low grade fever, fatigue and malaise which are signs that the immune system has been challenged and is mounting an immunogenic response and cranking up your antibody response. Take an acetaminophen or ibuprofen and the “storm” will pass. And be ready to be immunized again next season (until a Universal Influenza vaccine is developed).
Myth: Vaccines may cause autism!
Not true!!! This myth began after an article published in 1998 by the British journal The Lancet reported that the parents of eight children with autism believed they developed the condition after MMR vaccination (Measles, Mumps, Rubella). Since then, and despite a 2002 article published by the New England Journal of Medicine analyzing an impressive 530,000 children found no link between vaccinations and autism, rumors and irrational behavior have obligated public health authorities to mandate vaccination in some counties where parents left too many children without protection and “heard” immunity became compromised.
Reminder: if you were born after 1957, you should receive another MMR booster. Also, after review of new evidence, the FDA has indicated that expansion of HPV vaccination to age 45 may be beneficial.
We will address other “myths” in future communications.
In the meantime, remember: keep cool, eat a nutritious and diverse diet, limit supplements, stay active and be happy! The only fountain of youth proven by science, experience and millennia are exercise, laughter, humor and a good positive attitude! Enjoy every minute of the JOURNEY!