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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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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COVID-19: the big picture

Today Switzerland became the country with the highest rate of confirmed cases of corona virus per million population. Well, that is if you ignore some micro-populations such as the Vatican City, San Marino, Andorra and Faeroe Islands. Why?  It is landlocked with Italy, France and Germany around it. It did not close the border between Ticino and Italy for cross-border workers and many live in Italy were the virus spread rapidly. Also, it was the height of the ski season and alpine resorts were crowded with skiers from all over Europe, Britain and beyond. Here is a graph I did yesterday comparing confirmed cases per million population  for the thirty leading countries (excluding small countries with population less than one million. Data are from worldometers.com at 13.11 GMT on March 24. A this point Switzerland had not yet overtaken Italy.

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