[russellw]

There have also been a number of studies that have reported findings in the last week.

Pfizer - efficacy over 6 months
In a placebo-controlled, observer-blinded, multinational, pivotal efficacy trial, 44,165 participants 16 years of age or older received two does, 21 days apart, of BNT162b2 or placebo. The trial end points were vaccine efficacy against laboratory-confirmed Covid-19 and safety, which were both evaluated through 6 months after vaccination.

Vaccine efficacy against Covid-19 was 91.3% [89.0 - 93.2] through 6 months of follow-up among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated and there was only a gradual decline in vaccine efficacy. Vaccine efficacy against severe disease was 96.7% [80.3 - 99.9].

Household Contacts - Vaccine Effectiveness
Netherlands. The study extrapolated vaccine effectiveness against onward transmission by comparing secondary attack rates among household members between vaccinated and unvaccinated index cases, based on source and contact tracing data collected when Delta variant was dominant.

Effectiveness of full vaccination of the index against transmission to fully vaccinated household contacts was 40% [CI 20-54%] which is in addition to the direct protection of vaccination of contacts against infection.

Effectiveness of full vaccination of the index against transmission to unvaccinated household contacts was 63% [CI 46-75%]

This compares to the previously reported reported effectiveness of 73% [CI 65-79%] against transmission to unvaccinated household contacts for the Alpha variant.


Effects of Covid-19 pandemic on life expectancy in 2020
Source:37 upper-middle and high income countries or regions with reliable and complete mortality data. Note that Australia was not a participant in the study.

Data: Annual all cause mortality data from the Human Mortality Database for 2005-20, harmonised and disaggregated by age and sex.

Measure: Reduction in life expectancy was estimated as the difference between observed and expected life expectancy in 2020 using the Lee-Carter model. Excess years of life lost were estimated as the difference between the observed and expected years of life lost in 2020 using the WHO standard life table.

Exec Summary:
- Reduction in life expectancy in men and women was observed in all the countries studied except New Zealand, Taiwan, and Norway, where there was a gain in life expectancy in 2020.
- No evidence was found of a change in life expectancy in Denmark, Iceland, and South Korea.
- The highest reduction in life expectancy was observed in:
Russia (men: −2.33, women: −2.14);
United States (men: −2.27, women: −1.61);
Bulgaria (men: −1.96, women: −1.37);
Lithuania (men: −1.83, women: −1.21);
Chile (men: −1.64, women: −0.88); and
Spain (men: −1.35, women: −1.13).

Years of life lost in 2020 were higher than expected in all countries except Taiwan, New Zealand, Norway, Iceland, Denmark, and South Korea.

In the remaining 31 countries, more than 222 million years of life were lost in 2020, which is 28.1 million years of life lost more than expected - 17.3 million in men and 10.8 million in women.

The highest excess years of life lost per 100 000 population were observed in Bulgaria (men 7260, women 3730); Russia (men 7020, women 4760); Lithuania (men 5430, women 2640); USA (men 4350, women 2430); Poland (men 3830, women 1830) and Hungary (men 2770, women 1920).

The excess years of life lost were relatively low in people younger than 65 years, except in Russia, Bulgaria, Lithuania,and the US where the excess years of life lost was >2000 per 100 000.

Conclusion More than 28 million excess years of life were lost in 2020 in 31 countries, with a higher rate in men than women. Excess years of life lost associated with the covid-19 pandemic in 2020 were more than five times higher than those associated with the seasonal influenza epidemic in 2015.

Evaluation of the Pfizer Covid-19 Vaccine in Children 5-11 Years
Method A phase 1, dose-finding study and an ongoing phase 2–3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 M to 11 years of age. Note that this study was funded by Pfizer but has been peer reviewed.

We present results for 5-to-11-year-old children. In the phase 2–3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-μg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed.

Results: During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 μg, 20 μg, or 30 μg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 μg was selected for further study. In the phase 2–3 trial, a total of 2,268 children were randomly assigned to receive the BNT162b2 vaccine (1,517 children) or placebo (751 children). At data cut-off, the median follow-up was 2.3 months.

In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favourable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 [CI 0.93 to 1.18], a ratio meeting the prescribed immunogenicity success criterion. Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in sixteen placebo recipients for a vaccine efficacy of 90.7% [CI, 67.7 to 98.3].

Vaccination and Disease Severity (Pfizer & Moderna)
Question: Does prior COVID-19 vaccination reduce hospitalizations for COVID-19, and among patients hospitalized for COVID-19, does prior vaccination reduce disease severity?

Findings: In a case-control study that included 4,513 hospitalized adults in 18 US states, hospitalization for a COVID-19 diagnosis compared with an alternative diagnosis was associated with an adjusted odds ratio (aOR) of 0.15 for full vaccination with an authorized or approved mRNA COVID-19 vaccine.

Among adults hospitalized for COVID-19, progression to death or invasive mechanical ventilation was associated with an aOR of 0.33 for full vaccination.