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Why we dont know if plastics are safe

How can we determine conclusively whether a chemical is safe?

Thats the question Jerry Heindel, a t..



How can we determine conclusively whether a chemical is safe?

Thats the question Jerry Heindel, a top health scientist in the United States government, wanted to answer. And what better chemical to ask this question about than bisphenol A — one of the most researched chemicals in the world, and one of the most controversial.

BPA, as the chemical is known, is an industrial additive essential in the production of many plastic consumer goods: water bottles, plastic food containers, dental products. And yet, despite hundreds of studies dating back nearly a century, theres no scientific consensus on whether BPA is harmful to human health.

Thats in part because any effects the chemical has would be long-term, complicated and hard to detect. But its also because academic scientists and government regulators disagree on how best to evaluate the safety of chemicals.

The solution Heindel — at the time a health science administrator at the U.S. National Institute of Environmental Health Sciences — came up with was to design a study that would pull the two warring factions together in a single effort to assess the safety of BPA.

This is a story about what went wrong, and why scientists are no less sure than before about whether BPA is safe for human consumption.

Launched in 2012, Heindels study is the largest safety analysis ever attempted on the chemical. It mobilized scores of scientists and cost tens of millions of taxpayer dollars.

It has also failed, so far, in its goal of bridging the divide between scientists, imploding into acrimony last year when preliminary results published by the U.S. Food and Drug Administration sparked protests from the academics involved. A final conclusion on the safety of BPA also remains out of reach.

This is a story about what went wrong, and why scientists are no less sure than before about whether BPA — a chemical most of us probably have in our bodies — is safe for human consumption.

Blockbuster plastics

Rising worries about BPA coincided with the proliferation of plastics into every part of our economies and lives.

The word “plastics” covers a gamut of synthetic materials that are easy to manufacture, cheap to produce, and — with the help of chemical additives and processes — incredibly versatile. First mass-produced in the beginning of the 20th century, by the 1950s the material had became integral in everything from clothes and cars to furniture and food packaging.

“At the beginning it was just convenient to build a useful material,” Ninja Reineke, a senior policy adviser at the advocacy group ChemTrust, said. “They didnt take into account the potential implications.”

Researchers had known as early as the 1930s that BPA has a strange side-effect: It weakly mimics the hormone estrogen, which regulates the female reproductive system. But this curious consequence didnt stop petrochemical companies from using it — and using it a lot.

BPA is essential for the production of two blockbuster plastics: Epoxy resins, used as coatings for everything from electrical cables to shop receipts, and polycarbonate plastic, a hard, clear substance that has come to replace steel or glass in products from cars and electronics to water bottles and Tupperware.

By the late 1980s, nearly half a million tons of BPA were being produced per year in the U.S. alone.

Then, in 1992, scientists at Stanford University discovered that the chemical was “migrating” from the plastic, meaning it could be leaching from packaging into food or drinks and then into our bodies.

A sign in a French bio-supermarket | Joel Saget/AFP via Getty Images

In the early 2000s, a survey found BPA in the urine of more than 90 percent of Americans tested. What it couldnt say was whether that was a problem.

Low-dose effects

Evaluating the safety of substances that affect the hormone system, like BPA, is hard because they dont behave like most chemicals.

Traditionally, chemical regulation and the science it is based on rests on the assumption that the higher the concentration of a chemical, the more harmful it is. The dose makes the poison.

But a growing number of scientists believe that some widely used chemicals dont follow this trajectory, and can disrupt our hormonal systems even at very low levels. For these chemicals, they argue, setting strict exposure limits — a common form of regulation — is ineffective.

Effects on the endocrine system — which through a crowd of hormones regulates our metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood — can be hard to trace, because the balance of hormones in the body is precarious and affected by many factors.

And yet, amid all this noise a signal is emerging, according to the members of the Endocrine Society, which is made up of some 18,000 scientists around the world who study the endocrine system: Endocrine-disrupting chemicals like BPA are wreaking havoc on our bodies.

“They can really program your genes and development differently” — Ninja Reineke, a senior policy adviser at ChemTrust

The negative effects listed by the Endocrine Society include reduced fertility, diabetes, obesity and prostate cancer for men, and breast cancer for women.

Those concerned about endocrine disrupters say this group of chemicals has a number of unusual properties that make them behave similarly to hormones: Not only can they cause adverse effects even in very low amounts, these effects dont necessarily have an obvious trajectory curve when you increase the dose.

Instead of a steadily increasing linear graph, the charts used by scientists to illustrate their effects often wiggle like a sine curve.

Members of the Endocrine Society say the effects of chemicals like BPA dont always show up immediately. Hormone balance is most critical for fetuses and babies. Too much or too little of a hormone — or one of its mimics — early in life can throw off the development trajectory.

“They can really program your genes and development differently,” Reineke from ChemTrust said. “But it may not be obvious until later in life.”

Culture clash

So far, these findings — most of them made by scientists conducting research in universities — have failed to sway the government bodies that regulate chemicals like BPA.

Studies given the most weight by the FDA have to abide by a stringent set of bookkeeping requirements and laboratory best practices. This set of “good laboratory practices” (GLP) originated in a push to make sure that scientists werent cutting corners or faking data, but has since become the gold standard for regulators.

But while good laboratory practices are the norm for scientists working at the FDA or in industry-funded labs, many academics dont have the resources to meet their stringent requirements. Besides, academics have their own gold standard: peer-reviewed journals and university oversight.

The result is a culture clash that can sometimes produce wildly different conclusions — with regulators often discounting studies conducted by academics when assessing chemical safety.

“[Regulators] tend to put much more weight on studies that have been done according to guidelines, with lots of animals and the kind of record-keeping that allows them to repeat,” said John Bucher, from the U.S.s National Institute of Environmental Health Sciences. “Those kinds of studies are rarely done in the literature.”

The U.S. FDA has assessed the chemical multiple times at the point | Spencer Platt/Getty Images

The clash is particularly acute in the debate over BPA. The FDA has assessed the chemical several times. Each time, it has found that its safe at the levels in which it is present in food.

In the FDAs latest review of studies dealing with BPAs potential health impacts in 2014, the agency looked at hundreds of studies, including dozens that found cause for concern at low doses, conducted mostly by university scientists. It determined that only four of them met the standards for setting policy. None of the four found low-dose effects.

An FDA spokesperson said the review was carried out using “predefined, scientifically supported criteria for ranking each study,” and that even if many studies didnt meet the bar for setting regulatory values, “some studies were identified that did contribute qualitative information to support general conclusions” about whether BPA was harmful. The spokesperson added that extensive reviews of “low-dose” literature on BPA indicated that fears about the chemicals low-dose effects are not warranted.

Academics in response accused the FDA of cherry-picking data to support a preconceived conclusion. They also said that by not considering the work by university researchers, regulators are ignoring some of the best science on chemicals.

“The scientific apparatus worldwide is more advanced than its ever been, and yet its being largely ignored in chemical regulation,” said Thomas Zoeller, who studies thyroid hormone action and brain development at University of Massachusetts Amherst.

Ends and means

The main point of disagreement is over what exactly indicates a negative effect.

When determining the impact of a chemical on a specific organ, scientists use an array of “endpoints,” or markers of health effects, to track any changes. These could be the weight of an organ, the development of tumors or lesions, indicators of a disease, or an increase in the release of a bodily fluid or hormone, to name a few.

The FDA maintains a list of “validated” endpoints, which it says are acceptable because the effects can be replicated and they “best characterize risk” posed by a chemical. Before a chemical is identified as hazardous, the FDA said, it must proven that it has not just an effect, but a negative effect, on the body.

Some academics disagree with the FDAs approach. The agencys endpoints look mostly for “gross abnormalities,” according to Heather Patisaul, who studies endocrine disruptors and the brain at North Carolina State University.

“Theyre using such an insensitive marker. Brain weight doesnt reflect brain function” — Thomas Zoeller, reseracher

For example, one traditional endpoint for studies on brain development is the weight of the brain — if a chemical causes smaller brains to develop, its pretty likely that something is wrong.

But academics like Zoeller and Patisaul say many traditional endpoints wouldnt pick up the subtleties that a disruption of the endocrine system could cause.

“Theyre using such an insensitive marker,” said Zoeller. “Brain weight doesnt reflect brain function. Its like, if the engine isnt working in your car, its not really going to be informative to pull the engine out and weigh it.”

They point out that the FDAs endpoints list hasnt been updated in decades, since before the debate about endocrine disrupters or low-dose effects began. Instead, they advocate what they call more “modern” endpoints, which focus on signs of specific diseases.

Looking for CLARITY

Enter Jerry Heindel. His idea was to combine regulator-approved practices with academic expertise and modern endpoints.

Have the FDA raise and treat enough animals to satisfy the criteria for their study, and then once theyve done their research, ship some of the rats off to independent specialists, who can then take a look. At the end, both sides could combine their findings and determine once and for all whether BPA is safe.

The projects unwieldy name — the Consortium Linking Academic and Regulatory Insights on bisphenol A ToxicitY — was shorthanded to the CLARITY study in an optimistic nod to its goal.

Funded by the U.S. government, the study has in the seven years since its inception attracted the attention of regulators around the world, both for its work on the specific chemical and as an experiment in bridging the rift between academic and regulatory studies.

The U.S. government has funded the CLARITY study | Mandel Ngan/AFP via Getty Images

The European Food Safety Authority, notably, postponed its plans to re-evaluate the safety of BPA until the CLARITY study was published. The agency has also assessed the safety of the substance several times, arrivingRead More – Source

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NSW COVID-19 hospitalisations pass 1,000 as cases continue to balloon across Australia



sbs– New South Wales has recorded another 18,278 COVID-19 cases and two deaths as the state’s outbreak continues to surge.

Sunday’s case numbers are slightly lower than Saturday’s 22,577.

The state recorded two deaths from the virus, while 1,066 people are hospitalised, up from 901 on Saturday. There are 83 in intensive care.

At the peak of the Delta outbreak, on 21 September, there were 1,266 people hospitalised with infections, and 244 in intensive care.

Testing numbers to 8pm on the first day of 2022 were down to 90,019, a drop from 119,278 on New Year’s Eve.

The high case numbers come as Premier Dominic Perrottet continues to focus on hospitalisation and intensive care numbers rather than the daily case total.

Despite comprising about six per cent of the population, unvaccinated people make up the majority of those in intensive care, Health Minister Brad Hazzard says.

To ensure hospital systems can cope, asymptomatic health workers who are in isolation due to being a close contact of a positive case will be permitted to leave isolation in “exceptional circumstances”, NSW Health announced on Friday night.

Victoria posts 7,172 cases, extreme heat closes testing sites

The first day of 2022 hasn’t been kind to 7,172 Victorians, the state’s latest residents to contract COVID-19.

A further three virus-related deaths have also been recorded for 1 January.

However the number of Victorian coronavirus patients in hospital care remains relatively stable at 472, up 19 on Saturday’s figure and 48 beyond the seven-day average.

Of them, 52 are classified as active ICU cases and 22 are in need of ventilation.

Chief Health Officer Brett Sutton’s daily update said on Sunday community sampling had revealed 76 per cent of all samples collected over the Christmas period were the Omicron variant. Further testing to confirm this is being undertaken over the next week.

In total, Victoria is managing 31,461 active COVID-19 cases.

Health authorities says virus testers managed to process 48,252 results in the 24 hours to Saturday evening.

The state is 93 per cent fully vaccinated for everyone aged 12 and over.

Some 7,442 infections were reported on Saturday, another pandemic record. There were 51 actively infectious patients in intensive care and 21 ventilated.

Extreme heat caused the closure of eight of the state’s testing sites on Saturday.

Queensland records 3,587 new cases

Queensland has added 3,587 infections to its COVID-19 caseload as a new indoor mask mandate comes into effect across the state.

Some 16,688 Queenslanders now have the virus. However, hospital numbers remain low with 112 patients in care, five of them in ICUs and none requiring ventilation.

Health authorities say testers processed almost 34,000 results in the 24 hours to 7pm on Saturday.

Queensland is 86.60 per cent fully vaccinated for everyone 16 and over.

Chief Health Officer John Gerrard says despite a jump of more than 1,300 cases in a day, he’s not surprised. In part, the increase is related to a change in reporting protocols which saw case figures taken from a 12-hour window on Friday.

“This number is probably a bit smaller than we had expected,” he said in Brisbane on Sunday of the latest figures.

“It probably (also) relates to testing over the holiday period and so it will not be a surprise at all that in the next couple of days we see a significant increase in cases as more samples are tested and more people come forward.”

Dr Gerrard said what experts were now seeing with the virus was that it was “a vastly different disease” to that which was spreading in the community last year and prior to vaccination.

“With a degree of contagiousness of this virus, we are going to be seeing very large numbers of cases, even though the severity is clearly going to be less,” he said.

“We are going to see very large numbers of cases and a small proportion of a very large number (who fall ill) is still a large number.”

Masks were declared compulsory in “virtually all indoor spaces” in Queensland from 1am on Sunday.

Previously masks were only required indoors at supermarkets, shops, on public transport and ride share as well as airports and planes, cinemas and theatres in Queensland.

They now need to be worn at workplaces unless unsafe to do so, pubs, clubs and cafes unless when seated, indoor stadiums and sport arenas, libraries, hair dressers and nail salons, and medical centre waiting areas.

Queenslanders were also urged to return to work-from-home arrangements where possible.

SA hospitalisations ‘very much within capacity’

South Australia, meanwhile, recorded 2,298 COVID-19 cases on New Years Day from 21,140 tests.

The newest caseload is up from 2,108, while hospitalisations have also risen by 11.

There are currently 82 people in hospital, Premier Steven Marshall said on Sunday, a number which he said was “still very much within our current capacity”.

Seven people are in ICU.

“We see a lot of admissions but also a lot of people are leaving hospital on a daily basis after their conditions have stabilised,” Mr Marshall told reporters on Sunday.

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US follows UK’s lead and shortens isolation for healthcare workers who test positive for Covid-19



independent– Healthcare workers who test positive for Covid-19 and are asymptomatic only need to isolate for seven days, the Centers for Disease Control and Prevention (CDC) has said.

The CDC reduced the recommended isolation time from 10 days in part due to concerns that the highly transmissible Omicron variant could cause even greater staffing shortages at hospitals.

In new guidance released on Thursday, the CDC said infected healthcare workers could return to work after a week as long as they were asymptomatic and produced a negative test.

The US recorded 261,339 new cases on Thursday, according to data from Johns Hopkins University.

Earlier this week, the UK Health Security Agency announced that essential workers would be allowed to return after a seven-day isolation period amid a worsening staffing crisis in hospitals.

In a statement, CDC Director Rochelle Walensky said it was updating guidelines in response to an “anticipated surge” in patients due to the Omicron variant.

“Our priority, remains prevention—and I strongly encourage all healthcare personnel to get vaccinated and boosted.”

Dr Walensky added that health care workers who were fully vaccinated, including with a booster shot, did not need to isolate after a high-risk exposure.

On Friday, New York Governor Kathy Hochul announced that essential workers who tested positive could return to their jobs after five days if they were fully vaccinated and asymptomatic, and had not had a fever within the past 72 hours.

“This is not Delta, or the first variant,” Ms Hochul said during a live address.

“This is Omicron, and thus far it has demonstrated it’s not as severe in its impact, and therefore we want to make sure that our critical workforce, who we’ve relied on from the beginning, can get back to work.”

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Covid booster jab triggers immune response in days, not weeks, say scientists



independent– Those who receive a Covid booster jab can expect to mount an immune response in a matter of days – not weeks, scientists say.

The boosters have been shown to restore the body’s immunological defences against Omicron, which appears capable of infecting those who are double-jabbed.

While it takes up to two weeks to prime the immune system against Covid after a first dose, the effects of a booster jab start to be felt within two to three days, experts believe.

“The immunity generated after a booster jab will rise much quicker than the first immune response,” said Gary McLean, a professor in molecular immunology at London Metropolitan University.

That’s because crucial memory cells activated after the first dose will still be present in the body, Prof McLean explained, and therefore “do not require the two-week activation and instruction phase they initially go through”.

These memory cells – T and B – are responsible for hunting down infected cells and producing antibodies that stop the virus from gaining entry in the first place.

Their continuing presence means the immune system is on high alert and ready to spring back into action at the earliest sight of the virus, or anything that mimics it.

“That can then translate into boosted antibody levels and other increases in active T cells within days of the booster,” said Prof McLean. “It is likely that maximal immune activity is reached seven days after the booster.”

Professor Charles Bangham, an immunologist and co-director of the institute of infection at Imperial College London, said that in a secondary or subsequent immune response, T cells and antibodies should start to be detectable within “two to three days” of a booster.

The boosters appear to be 70 per cent effective against omicron infection – and are thought to offer even higher protection from hospitalisation and death – but scientists are concerned that the UK rollout won’t be able to keep up with the spread of the variant.

Doubling at a rate of every two days, Omicron has fuelled a sudden lift in national cases. On Thursday, 88,376 new Covid cases were reported, setting a new pandemic record for the second day running.

However, infections are thought to be running at far higher levels. The UK Health Security Agency said it expects there to be more than one million infections a day by the end of the month.

The government, meanwhile, has set the ambitious target of rolling out one million boosters a day to counter Omicron, and intends to have offered all eligible adults one by the close of the year. Some 745,183 third doses were given on Thursday, bringing the national total to 25.4 million.

Recent research from Israel suggests that rates of infection, severe disease and death from Delta were reduced after three to seven days post-boost – but reduced more after 12 days post-boost – when using the Pfizer vaccine for all three jabs.

The UK’s Cov-Boost study, which investigated the benefits of a booster jab among people who had received doses of the Pfizer or AstraZeneca vaccine, also pointed to an increased immune response by day seven.

“This ‘secondary immune response’ is more rapid than observed following the ‘priming’ course of vaccination, when the body takes 14 days or longer to ‘prime’ the antibody-producing B cells to produce antibody against the virus,” said Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London.

“However when virus antigens [an immune-triggering structure] are ‘re-encountered’ – either by a boosting shot of vaccine or by exposure to infection – these cells react very rapidly to produce antibody more quickly.”

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