Alzheimer's

Health experts across the globe are signalling alarm as they begin reporting that Omicron BA.5, the coronavirus strain that is currently outpacing other variants in infection and has become the dominant strain in the United States (US) and abroad, has the ability to reinfect people within weeks of contracting the virus. Andrew Robertson, the chief health officer in Western Australia, told News.com.au that though previously the wisdom held that most people would retain a certain level of protection against reinfection if they were vaccinated or had retained some level of natural immunity due to a recent contraction of the virus, this hasn’t been the case with the most recent strain. The ability of strains BA.4 and BA.5 to reinfect individuals who would in previous waves of COVID-19 had stronger immunity has led some experts to start calling this latest strain the most transmissible yet.

https://www.independent.co.uk/news/world/americas/ba5-covid-symptoms-omicron-reinfection-b2119725.html

With BA 5 occupying a dominant position, the share of tests that come back positive is shooting upward and is now higher than during most other waves of the pandemic. According to the US Centers for Disease Control & Prevention (CDC), the risk from COVID-19 is increasing in much of the country. (www.nytimes.com/interactive/2022/07/07/us/ba5-covid-omicron-subvariant.html?)

BA.5 and BA.4, both subvariants of the Omicron variant that swept the world during the winter, are the most capable versions of the virus yet at evading immunity from previous infections and vaccines. Both variants have mutations in their spike proteins that are different enough from earlier versions of the virus that they are able to dodge some antibodies.

In Portugal, where vaccination rates are higher than in the US, cases rose sharply after BA.5 became dominant in May, and hospitalisations neared their previous Omicron peak.

Before BA.4 and BA.5 became dominant in South Africa in April, research suggested that 98 percent of the population had some antibodies from vaccination or previous infection or both.

Even with those protective antibodies, many people in the country still became infected with BA.4 and BA.5, and the subvariants caused a small increase in cases, hospitalisations and deaths.

Places just emerging from significant spring waves of the virus may not be spared, either. Several countries in Europe had big outbreaks of a different Omicron subvariant, BA.2, that led to new waves of hospitalisations and deaths that peaked as recently as April. Yet in those countries, cases are going up again as BA.5 becomes dominant.

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The city of Shanghai has discovered a COVID-19 case involving a new subvariant Omicron BA.5.2.1, an official told a briefing on Sunday. https://www.reuters.com/world/china/chinas-shanghai-says-new-omicron-subvariant-found-2022-07-10/

Earlier, millions in Shanghai queued for a third day of mass COVID-19 testing on Thursday as authorities in several Chinese cities scrambled to stamp out new outbreaks. 

Unless local officials succeed in preventing the virus from spreading, they could be compelled to invoke prolonged, major restrictions on residents’ movement, under China’s “dynamic zero-COVID” strategy.

The country’s most populous city, Shanghai, has just emerged from a painful two-month lockdown and is again on high alert – racing to isolate infections. 

Shanghai reported 54 new locally transmitted COVID cases for Wednesday, versus 24 the previous day. 

Overall, mainland China reported 338 new local COVID cases for Wednesday, down from 353, with no new deaths, numbers that most countries would now consider insignificant.

www.medscape.com/viewarticle/976836?src=wnl_edit_tpal&uac=398271FG&impID=4411040&faf=1 

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Redesigned COVID-19 booster shots are expected in the US this autumn, after advisers to the Food and Drug Administration (FDA) voted 19-2 last week in favour of incorporating an Omicron strain into existing vaccines. (www.science.org/content/article/news-glance-debate-classifying-research-giant-water-lily-species-hummingbird-feather)

The FDA’s asking manufacturers to retool their shots for a spike protein component shared by Omicron BA.4 and BA.5, which are currently gaining ground worldwide. The new vaccines, which Pfizer and Moderna say they can make available by about October, will have the same messenger RNA dose as previous boosters but will target both Omicron and the original coronavirus strain first detected in 2019. 

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As monkeypox cases continue to rise globally, the World Health Organization  (WHO) is considering again whether to declare the outbreak a public health emergency of international concern. In late June, WHO’s Emergency Committee determined that the outbreak did not meet the criteria for such a declaration. Across the world, there have been more than 6,000 cases recorded in 58 countries,  WHO Chief Adhanom Ghebreyesus Tedros said. Monkeypox is a viral disease similar to smallpox that most commonly spreads from person to person through direct contact with infectious body fluids.

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Yet another much-anticipated Alzheimer’s medication, crenezumab, has proved ineffective in clinical trials — the latest of many disappointments. Public health experts and researchers argue that it is past time to turn our attention to a different approach — focusing on eliminating a dozen or so already known risk factors, like untreated high blood pressure, hearing loss and smoking, rather than on an exorbitantly priced, whiz-bang new drug. (www.nytimes.com/2022/07/03/health/dementia-treatment-behavior-eye-care.html?)

“It would be great if we had drugs that worked,” said Dr. Gill Livingston, a psychiatrist at University College London and chair of the Lancet Commission on Dementia Prevention, Intervention and Care. “But they’re not the only way forward.”

The latest modifiable risk factor was identified in a study of vision impairment in the United States that was published recently in JAMA Neurology. Using data from the Health and Retirement Study, the researchers estimated that about 62 per cent of current dementia cases could have been prevented across risk factors and that 1.8 per cent — about 100,000 cases — could have been prevented through healthy vision.

That’s because eye exams, eyeglass prescriptions and cataract surgery are relatively inexpensive and accessible interventions. “Globally, 80 to 90 per cent of vision impairment and blindness is avoidable through early detection and treatment, or has yet to be addressed,” Dr Joshua Ehrlich, ophthalmologist at the University of Michigan said.

The influential Lancet Commission began leading the modifiable risk factor movement in 2017. A panel of doctors, epidemiologists and public health experts reviewed and analysed hundreds of high-quality studies to identify nine risk factors accounting for much of the world’s dementia: High blood pressure, lower education levels, impaired hearing, smoking, obesity, depression, physical inactivity, diabetes and low levels of social contact.

In 2020, the commission added three more: excessive alcohol consumption, traumatic brain injuries and air pollution. The commission calculated that 40 per cent of dementia cases worldwide could theoretically be prevented or delayed if those factors were eliminated.

“A massive change could be made in the number of people with dementia,” said Dr. Livingston. “Even small percentages — because so many people have dementia and it’s so expensive — can make a huge difference to individuals and families, and to the economy.”

In fact, in wealthier countries, “it’s already happening as people get more education and smoke less,” she pointed out. Because the odds of dementia increase with age, as more people reach older ages, the number of dementia cases keeps rising. But the proportions are dropping in Europe and North America, where the incidence of dementia has fallen by 13 per cent per decade over the past 25 years.

Dr Ehrlich hopes the Lancet Commission will add vision impairment to its list of modifiable risks when it updates its report, and Dr Livingston said it would indeed be on the commission’s agenda.

Why would hearing and vision loss contribute to cognitive decline? “A neural system maintains its function through stimulation from sensory organs,” explained Dr. Julio Rojas, a neurologist at the University of California, San Francisco and a co-author of an accompanying editorial in JAMA Neurology. Without that stimulation, “there will be a dying out of neurons, a rearrangement of the brain,” he said.

Hearing and vision loss could also affect cognition by limiting older adults’ participation in physical and social activity. “You can’t see the cards, so you stop playing with friends,” Dr. Ehrlich said, “or you stop reading.”

The link between dementia and hearing loss, the single most important factor the Lancet Commission cited as a modifiable risk, has been well established. There is less clinical data on the connection to impaired vision, but Dr Ehrlich is a co-investigator of a study in southern India to see whether providing older adults with eyeglasses affects cognitive decline.

Even fairly routine medical practices, like measuring and monitoring high blood pressure and taking drugs to control it, can be difficult for low-income patients.

Still, despite the caveats and cautions, reducing modifiable risk factors for dementia could have enormous payoff, and the US CDC has incorporated that approach into its National Plan to Address Alzheimer’s Disease.

Even delaying its onset can have a great effect. “If, instead of getting it at 80, you get it at 90, that’s a huge thing,” Dr Livingston said.

Eye and hearing exams, exercise, weight control, stopping smoking, blood pressure medications, diabetes care — “we’re not talking about expensive interventions or fancy surgery or seeing specialists who are hours away,” Dr. Ehrlich added. “These are things people can do in the communities where they live.”

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Monday 11 July was World Population Day with the global population expected to reach 8 billion this year. 

In 2011 it was 7 billion.

Moving away from the Malthusian postulate that the human population grows more rapidly than the food supply until famines, war or disease reduces the population, UN Secretary-General António Guterres said: “Reaching a global population of eight billion is a numerical landmark, but our focus must always be on people. In the world we strive to build, 8 billion people means 8 billion opportunities to live dignified and fulfilled lives.”

Some population points:

• It took hundreds of thousands of years for the world population to grow to 1 billion – then in just another 200 years or so, it grew sevenfold. 
• In 2011, the global population reached the 7 billion mark, it stands at almost 7.9 billion in 2021.  
• It’s expected to grow to around 8.5 billion in 2030, 9.7 billion in 2050, and 10.9 billion in 2100.
• The world’s population more than tripled in size between 1950 and 2020.
• The growth rate of the world’s population reached a peak between 1965 and 1970, when human numbers were increasing by an average of 2.1% per year.
• From 2000 to 2020, even though the global population grew at an average annual rate of 1.2 per cent, 48 countries or areas grew at least twice as fast: these included 33 countries or areas in Africa and 12 in Asia. www.un.org/en/observances/world-population-day

Lalita Panicker is Consulting Editor, Views and Editor, Insight, Hindustan Times, New Delhi