Study: 'Extremely small' risk of blood clots with AstraZeneca COVID vaccine
Two independent UK studies published yesterday in PLOS Medicine find only a very slight risk of blood clots in the brain after receipt of the AstraZeneca/Oxford COVID-19 vaccine and none after the Pfizer/BioNTech vaccine. Both studies were led by University of Edinburgh researchers.
The first study involved analysis of the electronic health records of 46 million adults in England, 21 million of whom were vaccinated during the study period of December 2020 to March 2021.
After adjusting for demographic characteristics and underlying illnesses, the risk of blood clots blocking an artery or vein was slightly lower in the 28 days after vaccination with either the AstraZeneca or AstraZeneca vaccine in people 70 years and older. In people younger than 70, the risk was similar in the 28 days but rose slightly for venous blood clots in the brain after AstraZeneca.
This finding corresponded to an estimated excess risk of 0.9 to 3 per million, depending on age and sex, about twice that of unvaccinated people. The authors, however, said the benefits of COVID-19 vaccination likely exceed the risk.
"We were able to show that these risks occur only in people under 70 years old with the Oxford-AstraZeneca vaccine and that the increase in risk is extremely small—no more than a few people per million vaccinated," lead author William Whiteley, BM BCh, PhD, said in a PLOS news release.
The second study involved a dataset of 11.6 million adults in England, Scotland, and Wales from December 2020 through June 2021. The researchers compared rates of cerebral venous sinus thrombosis (CVST), a rare kind of blood clot in the brain, in the 90 days before vaccination with Pfizer or AstraZeneca with the rate in the 4 weeks after vaccination.
There was a small elevated risk of CVST after AstraZeneca vaccination, equivalent to one additional event per 4 million people vaccinated, or about twice as high as before vaccination. "This evidence may be useful in risk–benefit analyses of vaccine policies and in providing quantification of risks associated with vaccination to the general public," the researchers concluded.
Feb 22 PLOS Med study 1 and study 2
Feb 22 PLOS news release
Digital health consensus statement addresses COVID-19, future pandemics
A consensus statement by 13 international leaders in public health, digital health, and healthcare today in JAMA Network Open provides a roadmap for the implementation of digital health policy for healthcare and local, national, and international governments to address the COVID-19 pandemic and future crises.
Digital health refers to the use of computing platforms, networks, software, and sensors to improve the ability to diagnose and treat diseases.
The group created the Riyadh Declaration on Digital Health using the proceedings of the Riyadh Global Digital Health Summit in August 2020. Stakeholders identified high-priority issues within the themes of team, transparency and trust, technology, "techquity" (addressing health disparities), and transformation.
Their nine recommendations are to:
- Implement evidence-based protocols for effective communication to the public
- Work globally to address misinformation on social and mass media
- Develop a standard global dataset for public health reporting
- Ensure prioritization of digital health
- Provide technology to collect and share data quickly
- Develop a healthcare workforce able to address current and future public health crises
- Ensure that surveillance systems enable a public health response while respecting privacy
- Create digital personal tools and services to support disease prevention, testing, management, and vaccination
- Fund and create innovative surveillance systems for rapid preparedness and optimal global response
COVID-19 revealed weaknesses in global healthcare systems and public health responses, including the lack of long-term investment in digitization health information, collaboration, interoperability, and integrity, the authors said.
"The collection of data for public health surveillance was irregular…and few countries or communities had pandemic preparedness plans that enabled them to rapidly expand their data capture abilities to accurately monitor and track key outbreak information," they wrote. "Contact tracing had previously relied heavily on analog systems and could not be scaled up rapidly."
Implementation of the recommendations could ultimately lower fatalities and unite countries in confronting current and future pandemics, the authors said.
In a related commentary, Lennart Reifels, PhD, of the University of Melbourne in Australia, and Virginia Murray, MBBS, of the UK Health Security Agency, said that the recommendations, along with the World Health Organization's Global Strategy on Digital Health 2020-2025, "provide crucial policy drivers to advance the digital health agenda and guide local stakeholders to establish digital health systems and protocols that facilitate future disaster health preparedness and emergency management."
Feb 23 JAMA Netw Open consensus statement and commentary
H5 avian flu strikes Delaware poultry farm as Indiana reports fifth outbreak
Federal animal health officials today reported a highly pathogenic avian flu outbreak at a commercial poultry farm in Delaware, the sixth state to report the virus in poultry. Also, Indiana reported a fifth outbreak at a turkey farm.
Delaware's outbreak occurred in a flock in New Castle County, an area surrounding Wilmington that is on the coast of the Delaware Bay, according the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).
The Delaware Department of Agriculture (DDA) said the birds were tested after producers noticed increased deaths over the past few days. Officials said the detection involves the same highly pathogenic H5 strain that has been confirmed in other states and in wild birds along the Atlantic flyway. So far, the source of the virus isn't known. The event marks Delaware's first highly pathogenic avian flu outbreak in poultry since 2004.
The farm is under quarantine, and the birds will be depopulated. Earlier this month, the USDA reported eight Delaware H5 detections in hunter-harvested waterfowl, all involving H5 and one confirmed at H5N1. All were in Kent County, New Castle County's neighbor to the south.
In a related development, Indiana's Board of Animal Health (IBAH) today reported a fifth H5 outbreak, another involving a commercial turkey farm. The latest outbreak occurred in Dubois County, involving a flock of 35,908 birds, which will be depopulated. Three outbreaks have now been reported in Dubois County, but the latest location is 2.5 miles from the county's initial outbreak, so officials have established a fifth 10-kilometer surveillance zone.
So far, Indiana's outbreaks have affected 154,781 turkeys.
Feb 23 USDA APHIS statement
Feb 23 DDA statement
Feb 23 IBAH update
WHO sees more global signs of declining flu activity
Global flu activity is still at low levels and has declined more since it peaked at the end of 2021, the World Health Organization (WHO) said in its latest update, which covers the last week of January and the first week of February.
Northern Hemisphere activity trended down, with most detections involving the H3N2 strain and the influenza B Victoria lineage. Flu levels declined in most of Asia, including China
Only a few parts of the world reported increases, including northern Africa and some temperate parts of South America, where H3N2 activity increased.
Globally, of respiratory samples that tested positive for flu during the update period, 68.1% were influenza A and 31.9% were influenza B. Of the subtyped influenza A viruses, 93.6% were H3N2. And of the characterized influenza B viruses, all but four belonged to the Victoria lineage.
The WHO included its usual caveats that the flu surveillance information should be interpreted with caution, owing to measures to control COVID-19 and changes in surveillance due to the demands of the pandemic.
Feb 21 WHO global flu update