COVID-19 risk and benefit of vaccination

see also:

• coronaviridae / corona viruses (CoV)
• influenza
• viruses
• vaccines
• pandemics - influenza, coronavirus, Ebola
• COVID-19 coronavirus (2019-nCoV / SARS-CoV-2)
• the unwell patient after Covid-19 vaccination
• COVID-19 science
• Covid-19 in Australia
• Covid-19 in Victoria
• https://www.sciencemag.org/collections/coronavirus
• The Lancet's coronavirus archive
• Aust Gov. patient handout of Pfizer vaccination
• Aust. govt patient handout of AZ vaccination risks

• Covid-19 is NOT the common cold nor is it influenza and it should be avoided where possible
  • while many who are infected with Covid-19 have a minor illness akin to that of a common cold, unlike the common cold approximately 10% of other people (higher in at risk groups) will develop moderate to severe disease requiring hospitalisation and some of these will require admission to ICU, being placed on a ventilator, while others may die
  • whilst influenza causes a similar illness to many, and may kill some people, especially the vulnerable and the elderly, Covid-19 has a much greater propensity for severe illness and death, even in younger persons
  • unlike the common cold and influenza, it not only attacks the respiratory system but also the cardiovascular system with risks of blood clots, stroke, heart damage, as well as the long Covid syndrome of chronic fatigue, “brain fog”, etc.
• most people who are not vaccinated are likely to catch Covid-19 at some point in the pandemic
• vaccination has a dramatic reduction in risk not only of catching Covid-19 but also much lower likelihood of hospitalisation or death from Covid-19

• Astra-Zeneca / J&J vaccination
  • 1 in 100,000 -250,000 develop thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT) usually within the first 4 weeks after 1st dose
    • in Australia, the death rate from this complication if recognised and treated early results in an overall 1 in 1 million probability of death from this complication
  • allergic reactions
  • rare cases of inducing thyrotoxicosis due to subacute thyroiditis or Graves disease ¹⁾²⁾ which resolves over months
  • rarely, autoimmune/inflammatory syndrome induced by adjuvants (ASIA syndrome)
• mRNA vaccines (eg. Pfizer/Moderna)
  • 1 in 1 million young people may develop transient myocarditis usually within 1st week after dose although it is unknown at this stage of any long term morbidity resulting from this, and this is probably of similar rates of occurrence as with normal background incidence of pericarditis or myocarditis in the community
  • a 2025 UK study ³⁾ of electronic health records of 14 million 5-18 year olds showed:
    • COVID-19 infection led to 2.24 extra cases of myocarditis or pericarditis per 100,000 children and young people who had COVID-19. In contrast, those who were vaccinated, there were only 0.85 extra cases per 100,000 children and young people.
    • after a first COVID-19 diagnosis, risks of the five conditions studied (arterial and venous thrombosis, thrombocytopenia, myocarditis or pericarditis) were highest in the first four weeks and, for several conditions, stayed higher for up to 12 months. In contrast, after COVID-19 vaccination, the team only saw a short-term higher risk in myocarditis or pericarditis in the first four weeks.
  • allergic reactions
  • rare cases of inducing thyrotoxicosis due to subacute thyroiditis or Graves disease ⁴⁾⁵⁾ which resolves over months
  • rarely, autoimmune/inflammatory syndrome induced by adjuvants (ASIA syndrome)

• vaccinated persons appear to have a 5x lower risk of catching Covid-19 and a 10x lower risk of catching Covid-19 requiring hospitalisation⁶⁾
  • so far in NSW 2021 up to end of Sept 2021, all deaths from Covid-19 in vaccinated people are in those aged over 50yrs whereas a number of deaths in those under 40yrs have occurred who are not vaccinated
    • see https://www.abc.net.au/news/2021-09-29/why-a-small-number-of-fully-vaccinated-people-have-died-of-covid/100497770
• at sufficiently high levels of vaccination (perhaps 84-92% of population double dosed), herd immunity may end the pandemic to such an extent it becomes mainly a endemic illness primarily of young children.

The following assumes 80% of unvaccinated adults will eventually be infected by Covid-19 and one fifth this proportion (15%) of vaccinated will be infected. Covid case fatality rates at present for adults under age 60 yrs is probably around 1 in 1000 (0.1%) hence this is the conservative figure used here.

Although young adults under 30yrs of age have CFR of around 1 in 10,000, a large study from the United Kingdom showed 27% of 19 to 29-year-olds admitted to hospital suffered some form of organ damage to the liver, lungs or kidneys — any of which can lead to permanent disability and a separate study showed 14% of patients under 40 admitted to ICU died, compared with 31% across all ages.⁷⁾