Effectiveness of Covid-19 vaccination against risk of symptomatic infection, hospitalization, and death up to 9 months: a Swedish total-population cohort study
Peter Nordstrom, MD, PhD peter.nordstrom at umu.se, Marcel Ballin, MSc., Anna Nordstrom, MD, pmd
- Department of Community Medicine and Rehabilitation, Unit of Geiiatric Medicine, Umea University, Umea, Sweden (Peter Nordstrom and Marcel Ballin)
- Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umea University, Umea, Sweden (Marcel Ballin and Anna Nordstrom)
- School of Sport Sciences, UiT the Arctic University of Norway, Tromso, Norway (Anna Nordstrom)
After 9 months some people who had gottten vaccinated were
MORE LIKELY to get infected than those who had not been vaccinated
Background: Whether vaccine effectiveness against Coronavirus disease 2019 (Covid-19) lasts longer than 6 months is unclear.
Methods: A retrospective cohort study was conducted using Swedish nationwide registries. The cohort comprised 842,974 pairs (N=1,684,958), including individuals vaccinated with 2 doses of
- ChAdOxl nCoV-19,
- mRNA-1273, or
- BNT162b2,
and matched unvaccinated individuals. Cases of symptomatic infection and severe Covid-19 (hospitalization or 30-day mortality after confirmed infection) were collected from 12 January to 4 October 2021.
Findings: Vaccine effectiveness of BNT162b2 against infection waned progressively from 92% (95% CI, 92-93, P<0-001) at day 15-30 to 47% (95% CI, 39-55, P<0-001) at day 121-180, and from day 211 and onwards no effectiveness could be detected (23%; 95% CI, -2-41, P=0-07). The effectiveness waned slightly slower rr mRNA-1273, being estimated to 59% (95% CI, 18-79) from day 181 and onwards. In contrast, effectiveness of ChAdOx1 nCoV-19 was generally lower and waned faster, with no effectiveness detected from day 121 and onwards (-19%, 95% CI, -97-28), whereas effectiveness from heterologous ChAdOx1 nCoV- 19 / mRNA was maintained from 121 days and onwards (66%; 95% CI, 41-80). Overall, vaccine effectiveness was fver and waned faster among men and older individuals. For the outcome severe Covid-19, effectiveness waned from 89% (95% CI, 82-93, P<0-001) at day 15-30 to 42% (95% CI, -35-75, P=0-21) from day 181 and onwards, with sensitivity analyses showing notable waning among men, older frail individuals, and individuals with comorbidities.
Interpretation: Vaccine effectiveness against symptomatic Covid-19 infection wanes progressively over time across all subgroups, but at different rate according to type of vaccine, and faster for men and older frail individuals. The effectiveness against severe illness seems to remain high through 9 months, although not for men, older frail individuals, and individuals with comorbidities. This strengthens the evidence-based rationale for administration of a third booster dose.
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Swedish preprint is based on very recent data (thru Oct 4) for >1,000,000 people for 3 vaccines
No indications of effectiveness against asymptomatic infections or those that resulted in death
- Fully Vaccinated Are COVID 'Superspreaders,' says Inventor of mRNA Technology - Oct 13, 2021
- Do not know if vaccinated are superspreaders, but it is a possibility.
- - - VACCINATED - - -
1) Are 100X more infectious when infected
2) Are infectious for 4X longer time
3) Tend to no longer wear masks, so spread the infection more than unvaccinated
4) Have more access to public places - restaurants, airplanes, international travel, etc
- Do not know if vaccinated are superspreaders, but it is a possibility.
- COVID-19 cases vs. vaccination (counties and countries) - Sept 2021
- Vaccinated were 28 percent of cases, 23 percent of deaths (waning)- CDC Sept 2021
- Pfizer vaccine half as effective as Moderna after 6 months (fading or Delta) - Mayo preprint Aug 2021
- Vaccinated and Unvaccinated are just as infectious after catching COVID-Delta (UK study) - Aug 2021
- Vaccine effectiveness may drop to only 16% in 6 months if time between jabs was only 3 weeks – July 2021
- Note; Swedish study found ~20% effectiveness at 180 days - very close agreement
- Hypothesis by VitaminDWiki - body takes more notice of warnings when there is more time between the warnings
- ''Sweden extended the gap
between jabs to 6 weeks in mid March''