Vaccination is highly protective against Covid-19

As in Europe, the US is currently experiencing a surge in Covid-19 cases and hospitalizations driven by transmission among the unvaccinated.  Two days ago, health officials in Vermont noted that 90% of Covid cases in Intensive Care Units are unvaccinated. Currently 74% of the Vermont population is fully vaccinated. This information allows us to do a simple calculation using only high school algebra to estimate the difference in risk of severe Covid infection among vaccinated compared to unvaccinated.

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Booster shots and the current Covid-19 Delta wave

Switzerland is now offering a covid19 booster shot to to the 65+ and at-risk who has had their two covid19 vaccinations at least six months ago. It may soon be extended to all adults. I had my third shot last Thursday with no side effects (not even a localized sore spot) and was surprised to receive a Pfizer booster after being fully vaccinated earlier this year with the Moderna vaccine. The mRNA in both vaccines encode the same S-2P protein which differs from the covid19 spike protein by two amino acids only. These stabilize the spike protein so that it can train the immune system before it enters the host cell. I’ve been reading up on booster shots and will try to provide a brief summary below. If you want citations and more detail on the studies, see my professional blog here.

A large study of 1.14 million Israeli adults, aged 60 years and over who had received two Pfizer doses at least 5 months earlier, found that a third shot reduces the risk of infection by the dominant Delta variant by a factor of 11 compared to fully vaccinated people who have had two shots.  Receiving a different vaccine type as I did, further reduces the risk by around 30% or more. The booster shot lowers the risk of severe illness even more, by a factor of around 20 compared to those who have had two shots only.

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A fourth Covid-19 wave hits Europe and Switzerland has a second referendum to end vaccine certificate requirements

Covid-19 cases rose by 7% and deaths by 10% over the last week in Europe, as it enters a fourth (or fifth) wave and currently accounts for about two-thirds of infections reported globally. Belgium and the Netherlands, which have fully vaccinated 73-74% of their populations, have the highest new case rates in Western Europe, almost double those of Britain. The fully vaccinated rate is Switzerland is 64%, higher than the USA at 57% but lower than Australia now at 69%.

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Why do Americans die earlier than Europeans?

A recent paper by demographers Sam Preston and Yana Vierboom showed that there are an additional 400,000 deaths in the USA in 2017 that would not have occurred it the USA experienced European death rates. That is about 12% of all American deaths and higher than the COVID-19 death toll of around  380,000 in 2020.  In a Guardian article earlier this month they identified major factors contributing to this US “mortality penalty” including overweight and obesity, drug overdose, lack of health insurance, suicide, lack of gun control and racism. These deaths tend to occur at younger ages than Covid deaths on average, so that total potential years of life lost are three times greater for the excess deaths than for Covid in 2020 (13 million versus 4.4 million).

Preston and Vierboom used data from the Human Mortality Database (HMD) for their analysis. They calculated death rates based on the five largest European countries, whose combined population size is very similar to that of the United States: Germany, England and Wales, France, Italy, and Spain. They also argued that using these larger European countries  to provide a mortality standard would avoid unrealistic expectations that might result from comparisons including small countries with possibly exceptional combinations of factors affecting mortality (e.g., climate, diet, social history, and healthcare delivery).

A few days ago, I downloaded updated data from the HMD and replicated and extended their analysis to include years up to and including 2020, drawing on recent data from Eurostat and national health statistics agencies (see here for details of data, sources and methods).

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The twin pandemics and the second wave

Today, I took another look at the second wave of the Covid-19 pandemic using data on confirmed new cases per day. The first figure shows four countries where the second wave has peaked and is coming down. Australia is somewhat unique in that its second wave peaked considerably higher than the first. Croatia and likely Spain will join that club.

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A pandemic out of control

Over the last two days, I’ve been assessing the coronavirus situation across the world. I’ve posted a regional analysis of trends in new cases on my professional site (an-out-of-control-pandemic-in-most-world-regions).

I reproduce a graph of regional trends below. The dramatic difference in trajectories for Western Europe and the Americas is obvious. While levels are lower in most developing regions, this is mostly due to much lower levels of testing. But confirmed new cases in all regions apart from Europe and East Asia and Pacific are rising.

North America has the most out-of-control epidemic, and that is all due to the USA. I plotted trends for blue and red states in the USA. There is a dramatic difference, with most of the recent rise in new cases occurring in red states (that voted for Republican presidents in most of the recent presidential elections). In the week ending July 5, there were an average 226 new cases per 1 million population in red states compared to 88 per million in blue states.

In a second post which-countries-are-succeeding-and-not-succeeding, I have shown country-specific plots for selected examples of three groups of countries: (1) those that are beating Covid-19, (2) those that are nearly there, and  (3) those that need to take action.  The experiences of the first two groups of countries show that (a) it is important to act early, not wait till there a hundreds of deaths in the country, (b) it only takes about 5-7 weeks of strong interventions to get rid of the majority of cases and (c) half measures don’t work.

COVID-19: light at the end of the tunnel for some countries

Tomorrow, Switzerland will relax its social distancing regime. Classroom teaching at primary and lower secondary schools will again be permitted. Shops, markets, museums, libraries, gyms and restaurants will be able to reopen under strict compliance with precautionary measures. Switzerland has had the 10th highest death rate per million people but has been one of the few high death rate countries to successfully control the epidemic. See the plot for Switzerland below.

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COVID-19 short-run projections

Its now one month since my earlier post on the coronavirus pandemic    A lot has changed since then. We have gone from 24,392 deaths globally on March 26 to 206,915 on April 26th. And recent analysis of total registered deaths by week in February and March, compared to the same periods in the previous year, suggest that the reported deaths (mostly hospital deaths) are only about 70% of the actual deaths. The proportion of deaths reported in developing countries without good death registration (including most of Africa, and much of Asia) will be even lower.

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