Showing posts with label polio. Show all posts
Showing posts with label polio. Show all posts

Monday 10 May 2021

Vaccine hesitancy is nothing new. Here’s the damage it’s done over centuries

“Vaccine hesitancy has less to do with misunderstanding the science and more to do with general mistrust of scientific institutions and government,” says Maya Goldenberg, a philosophy expert at the University of Guelph, Ontario, who studies the phenomenon. Historically, people harmed or oppressed by such institutions are the ones most likely to resist vaccines, adds Agnes Arnold-Forster, a medical historian at the University of Bristol in England.

‘A range of recurring and intersecting themes have fueled hesitancy globally and historically. These include anxiety about unnatural substances in the body, vaccines as government surveillance or weapons, and personal liberty violations. Other concerns relate to parental autonomy, faith-based objections, and worries about infertility, disability or disease. For example, some people oppose vaccines that were grown in cell culture lines that began from aborted fetal cells, or they mistakenly believe vaccines contain fetal cells. One of today’s false beliefs — that COVID-19 vaccines contain a microchip — represents anxiety about both vaccine ingredients and vaccines as a surveillance tool.’

Read here (Science News, May 11, 2021)

Saturday 20 March 2021

We need social science, not just medical science, to beat the pandemic

‘The polio pandemic of the 1950s is another often-ignored “teachable” moment. On the surface, it would seem that it was a scientific, medical and policy success story. But the reality is closer to what we are seeing with COVID.

‘In 1954, when polio was at its most virulent, the Eisenhower administration declared that every child should receive the polio vaccine being developed at that time. But there was no cohesive plan at the federal level to make that happen, so the mandate was not a success. In addition, lack of oversight regarding the quality of the vaccine manufacturing process led to some children becoming sick or dying. Limited resources to administer the vaccine on a national scale were another problem, and it was not until Eisenhower’s signing of the Polio Vaccination Assistance Act in 1955 that there were enough federal funds available for a national public inoculation program. Such massive confusion resulted in public distrust that took years to abate.

‘When the sociologist Alondra Nelson was named as the new deputy director of the Office of Science and Technology Policy [in 2021], she noted that the pandemic had “held up a mirror to our society, reflecting … the inequality we’ve allowed to calcify.” She also noted that “science is a social phenomenon.” This implies not just that science requires real insight into the society with which it interacts, but also that it is forged in relationship to social forces and meanings. Social science can assist us in understanding social reactions to scientific knowledge, as well as in ensuring that science becomes aware of its own social biases and interests.’

Read here (Scientific American, Mar 20, 2021)

Monday 1 March 2021

The raging evolutionary war between humans and Covid-19

‘Fighting the pandemic isn’t only about vaccines and drugs. It’s about understanding how viruses mutate and change inside us, and among us...

‘The major change to the immunity of all the hosts SARS-CoV-2 is likely to try to infect will be, of course, vaccination. That’s human ingenuity fighting viral expertise, but it can also exert a kind of direct adaptive pressure on the virus. History has examples of so-called leaky vaccines—those that aren’t effective enough to prevent all infections or all transmission, and allow better-adapted variants of whatever bug they’re trying to squish to live to fight another day.

‘In fact, one group of researchers has a model that suggests that could even happen with the new batch of vaccines against Covid—especially those that require two doses and seem to confer different levels of immunity depending on how far apart they’re administered, or whether someone skips the second one. Here's how: If one extreme is a population totally naive to a new virus, completely vulnerable and with no immunity, and the other extreme is a population with perfect sterilizing immunity, what happens to a population in between? If a vaccine allows infection but no transmission, the virus doesn’t have a chance to evolve.

‘But if a vaccine or vaccination strategy allows some infection and some transmission? “The ones that are the best at getting around the host’s defenses are the ones that are most likely to persist,” says Caroline Wagner, a bioengineer at McGill and one of the people working on the model. If that’s all true, a leaky vaccine or leaky vaccination strategy could actually drive antigenic drift and create even worse variants. Wagner and her colleagues acknowledge that they don’t have enough data to put bounds on their model yet, but they worry about strategies like one proposed in the UK to abandon second doses as a way of speeding the process and husbanding scarce vaccine, or the way some countries are hoarding vaccine while others go without (potentially letting the virus, and variants, circulate and evolve freely).’

Read here (Wired, Mar 1, 2021)

Monday 18 January 2021

Vaccines need not completely stop Covid transmission to curb the pandemic

‘Influenza may provide the best blueprint of what to expect going forward. The most common flu vaccine—the inactivated virus—is not “truly sterilizing because it doesn’t generate local immune response in the respiratory tract,” Crowcroft says. This fact, coupled with low immunization rates (often shy of 50 percent among adults) and the influenza virus’s ability to infect and move between multiple species, enables it to constantly change in ways that make it hard for our immune system to recognize. Still, depending on the year, flu vaccines have been shown to reduce hospitalizations among older adults by an estimated 40 percent and intensive care admissions of all adults by as much as 82 percent.

‘Research on seasonal coronaviruses suggests that SARS-CoV-2 could similarly evolve to evade our immune systems and vaccination efforts, though probably at a slower pace. And data remain mixed on the relationship between symptoms, viral load and infectiousness. But ample precedent points to vaccines driving successful containment of infectious diseases even when they do not provide perfectly sterilizing immunity. “Measles, diphtheria, pertussis, polio, hepatitis B—these are all epidemic-prone diseases,” Crowcroft says. “They show that we don’t need 100 percent effectiveness at reducing transmission, or 100 percent coverage or 100 percent effectiveness against disease to triumph over infectious diseases.”

Read here (Scientific American, Jan 18, 2021)

Sunday 12 April 2020

Clinical trials on repurposing two vaccines, BCG and polio: Both statements start with "There is no evidence..."

On polio: ’There is no evidence that oral poliovirus vaccine (OPV) protects people against infection with COVID-19 virus. A clinical trial addressing this question is planned in the USA, and WHO will evaluate the evidence when it is available. In the absence of evidence, WHO does not recommend OPV vaccination for the prevention of COVID-19.’

Download here (Polio Eradication Initiative, March 2020)

On BCG: ‘There is no evidence that the Bacille Calmette-GuĂ©rin vaccine (BCG) protects people against infection with COVID-19 virus. Two clinical trials addressing this question are underway, and WHO will evaluate the evidence when it is available. In the absence of evidence, WHO does not recommend BCG vaccination for the prevention of COVID-19. WHO continues to recommend neonatal BCG vaccination in countries or settings with a high incidence of tuberculosis.’

Read here (WHO, April 12, 2020)

Worst ever Covid variant? Omicron

John Campbell shares his findings on Omicron.  View here (Youtube, Nov 27, 2021)