I hope you all had a happy and safe Easter break. There is quite a lot to talk about this week, so this will be quite long, but please bear with me.
The snapshot shows that worldwide there is only a tiny rise this week compared with last week, and this is mostly due to the big increases in both cases and deaths in the Western Pacific (Philippines, Malaysia, and to some extent PNG) and SE Asia (mainly India and Bangladesh). There are falls elsewhere.
Somebody who actually reads this weekly update asked me this week why the case fatality rate falls as an outbreak (including a pandemic) progresses, so for those who are interested here is a summary of the discussion:
- In my experience the case fatality rate (CFR) always drops as an outbreak progresses. This is because there are a few things going on at the same time.
- The age of cases also falls as an outbreak progresses, and I suspect that in a major outbreak (pandemic) this is no different, although we cannot see it as these data are not published (NOTE: I really wish we knew much more about the epidemiology but nobody seems to be publishing it – it would really help with containment strategies etc). Younger people by-and-large mount a better immune response to most things, so it is not surprising that they are more likely to survive. In fact, with some outbreaks – e.g. legionella – the CFR is very, very high at the start. If you look at the spreadsheet for Australia you will see that the CFR is much higher in Victoria than the other states except for Tasmania which has managed to fly under the radar – and this reflects the older population which suffered as a result of COVID infections managing to get into local aged care facilities where there were very high rates of infection and consequently fatalities.
- Secondly, the least fit people are normally the most likely to die, and because transmission happens before any preventive measures are put in place (for COVID, no social distancing etc.) clusters occurred in aged care etc, i.e. places where groups of similarly frail people (i.e. not people running around on the local high street or park) spend time or live.
- The third thing is that as outbreaks progress, effective treatment options become clearer. There are now a few – albeit very few – treatment/symptom mitigation options for COVID cases, so people are less likely to die (for COVID this is not as marked an effect as it is for bacterial disease outbreaks). HIV is an example of an erstwhile fatal disease which is now considered to be a chronic infection (at least in western countries).
- PLUS: all microorganisms evolve to maximise their survival. I am not anthropomorphising germs, but it is usual to see them becoming a bit easier to transmit but less likely to be fatal as time goes on. This is what appears to be happening in the UK, where new variants seem to have an R-rate (remember that?) of nearer 3 than 2.
The vaccination tracker is beginning to make some sense – but only some – as by now the effects of the programmes with higher coverage, especially Israel (which still seems to be having 500+ cases daily), should be showing in reduced cases, but aren’t really. Some countries which have been promised vaccines – such as Palestine and our Australian neighbour PNG – seem to have not begun vaccinating yet, which is a concern. The WHO COVAX programme continues to emphasise the importance of vaccines being available to all, and that intellectual property rights need to be suspended in order that all countries have access, as the programme need to be successful worldwide for all of us to be protected; but some countries are not playing that particular game.
This is highlighted in the several news reports this week, which I am including as there is a lot to say but I can’t see the point of repeating these articles which already say it well, so here you are:
1. What scientists do and don’t know about the AstraZeneca COVID vaccine (Nature, 25th March) – includes information about Astra Zeneca (AZ) vaccine efficacy, how it will help interrupt the pandemic, and vaccine safety. The Pfizer and Johnson & Johnson vaccines are also mentioned.
2. From the BBC: AstraZeneca: Is there a blood clot risk?, a comprehensive analysis with interviews with several very vaccine-reputable scientists. Also goes into why the AZ venous CVST clot rates are different in Germany compared with the UK (spoiler alert – different groups being given the vaccine).
3. From The Guardian: Experts stress vaccine benefits outweigh risks after seven UK deaths – an overview of who has and has not stopped using the AZ vaccine, who has recommenced use, and comments about the AZ blood clots from the UK team.
The last word here goes to Dr June Raine, UK’s Medicines and Healthcare products Regulatory Agency (MHRA) chief executive, who said the agency was continuing to conduct a thorough review of the reports, but vaccinations would continue…“The benefits of Covid-19 vaccine AstraZeneca in preventing Covid-19 infection and its complications continue to outweigh any risks and the public should continue to get their vaccine when invited to do so,” she said.’ (quote from website).
4. And now for a bit of conspiracy theory news: Vitamin D: The truth about an alleged Covid ‘cover-up’. This is a discussion about the nature of scientific evidence.
5. Why is it so hard to investigate the rare side effects of COVID vaccines? Also from Nature, discusses correlation not being proof of causation in some detail, and why monitoring of uncommon events is both difficult and important.
6. Why vaccines aren’t enough to control this pandemic. We hoped that mass vaccination would bring the pandemic to an end, but here’s how COVID variants complicate that picture, write members of the Lancet COVID-19 Commission Taskforce on Public Health.
7. EU denies blocking 3.1m Covid vaccine doses from reaching Australia. For Australian readers wanting more information about where the vaccines actually are, this is interesting.
8. How about a creative way to use quarantine time – something to make you smile: Horsing around: Australian man creates paper pony out of lunch bags in hotel quarantine
We are also reminded that there are problems other than COVID in the world:
9. There’s another pandemic under our noses, and it kills 8.7m people a year – a discussion about the health effects of air pollution.
Finally, First Dog nails it again…
Congratulations, you have made it to the end!
See you next week, stay safe.
About Dr Priscilla Robinson and The CODE Update
Dr Robinson is a public health epidemiologist with particular interests in international health and communicable diseases, and public health competencies. She has worked in health departments in England and Australia, has managed public health teaching programmes, and taught and researched many aspects of public health epidemiology and policy in many countries. She is an adjunct Associate Professor at LaTrobe University, and to stop herself being bored is an editor of PHAA’s journal ANZJPH, and holds board positions (almost all unpaid) on various NGOs, journals, and at her local hospital. Otherwise, 10 acres of untamed bushland on a hill in South Gippsland makes weight-bearing gym exercise and strength training a bit redundant.
The CODE Update is a new regular feature on the Intouch blog to keep readers informed of COVID-19 developments around the world.
The CODE update originally began at the start of the SARS CoV-2 pandemic as a way of explaining it to Priscilla’s friends and family who happen to live all over the world, and who were being bombarded with information and misinformation in their own countries. The CODE Update provides links to practical materials and papers written for people who are not versed in the language of outbreaks and epidemic curves. It is sent out every week, and includes a short commentary to provide context to the numbers included in the spreadsheets.
Note: Whilst every attempt is made to transcribe all data faithfully, every now and again mistakes are made and not noticed until the next update. Also, on occasion numbers are revised after posting at the source databases.
We hope you will find these updates to be a helpful tool, and the links to current information useful.