Data Doesn’t Support Need for COVID-19 Vaccine Boosters: Experts

COVID-19 vaccine booster shots might not be needed for most people, according to a large international review.

The review — conducted by a team that included scientists from the World Health Organization and the U.S. Food and Drug Administration — concluded that current vaccines are effective enough against severe COVID-19, even from the Delta variant, and that booster shots are unnecessary.

The findings, published in The Lancet, are based on a review of all available published literature and results of clinical trials.

“The vaccines that are currently available are safe, effective, and save lives,” said study co-author Dr. Soumya Swaminathan, chief scientist at the WHO.

“Although the idea of further reducing the number of COVID-19 cases by enhancing immunity in vaccinated people is appealing, any decision to do so should be evidence-based and consider the benefits and risks for individuals and society,” she said in a journal news release. “These high-stakes decisions should be based on robust evidence and international scientific discussion.”

According to the review, vaccines were 95% effective against severe disease both from the Delta and Alpha variant, and more than 80% effective at protecting against infection from these variants.

Vaccines are less effective against asymptomatic disease or transmission than against severe disease, according to the review. It added that unvaccinated people are the major drivers of transmission and are at the greatest risk of severe disease.

“Taken as a whole, the currently available studies do not provide credible evidence of substantially declining protection against severe disease, which is the primary goal of vaccination,” said lead author Dr. Ana Maria Henao-Restrepo, a medical officer at the WHO’s Initiative for Vaccine Research.

She said the limited supply of vaccine will save the most lives if made available to unvaccinated people who are at risk of serious disease.

“Even if some gain can ultimately be obtained from boosting, it will not outweigh the benefits of providing initial protection to the unvaccinated,” Henao-Restrepo added. “If vaccines are deployed where they would do the most good, they could hasten the end of the pandemic by inhibiting further evolution of variants.”

Although antibodies in vaccinated people wane over time, the authors noted that it does not predict that a lack of protection against severe disease.

Protection against severe disease is not only from antibody responses, which might be short-lived for some vaccines, but also by memory responses and cell immunity, which are longer-lived, the researchers explained. If boosters are needed, they would be in circumstances where the benefits outweigh the risks.

Even without any loss of effectiveness, however, increasing success in delivering vaccines to large populations will lead to increasing more widespread immunization, the researchers said. As a result, more cases that do occur would be less severe breakthrough infections, especially if vaccination leads people to change their behavior.

But, they added, the ability of vaccines to elicit an antibody response against current variants indicates that these variants have not yet evolved so much they are likely to escape the protection by the vaccines.

If boosters are needed, the researchers said, they would most likely be developed against specific variants not covered by current vaccines. This strategy is like that for flu shots, which changes as flu strains evolve from year to year.

Source: HealthDay

In Pictures: Food of Épure in Tsim Sha Tsui, Hong Kong

Fine Dining Contemporary French Cuisine

The Michelin 1-star Restaurant

Elevated Stress Hormones Linked to Higher Risk of High Blood Pressure and Heart Events

Adults with normal blood pressure and high levels of stress hormones were more likely to develop high blood pressure and experience cardiovascular events compared to those who had lower stress hormone levels, according to new research published today in Hypertension, an American Heart Association journal.

Studies have shown that cumulative exposure to daily stressors and exposure to traumatic stress can increase cardiovascular disease risk. A growing body of research refers to the mind-heart-body connection, which suggests a person’s mind can positively or negatively affect cardiovascular health, cardiovascular risk factors and risk for cardiovascular disease events, as well as cardiovascular prognosis over time.

“The stress hormones norepinephrine, epinephrine, dopamine and cortisol can increase with stress from life events, work, relationships, finances and more. And we confirmed that stress is a key factor contributing to the risk of hypertension and cardiovascular events,” said study author Kosuke Inoue, M.D., Ph.D., assistant professor of social epidemiology at Kyoto University in Kyoto, Japan. Inoue also is affiliated with the department of epidemiology at the Fielding School of Public Health at the University of California, Los Angeles.

“Previous research focused on the relationship between stress hormone levels and hypertension or cardiovascular events in patients with existing hypertension. However, studies looking at adults without hypertension were lacking,” Inoue said. “It is important to examine the impact of stress on adults in the general population because it provides new information about whether routine measurement of stress hormones needs to be considered to prevent hypertension and CVD events.”

Study subjects were part of the MESA Stress 1 study, a substudy of the Multi-Ethnic Study of Atherosclerosis (MESA), a large study of atherosclerosis risk factors among more than 6,000 men and women from six U.S. communities. As part of MESA exams 3 and 4 (conducted between July 2004 and October 2006), white, Black and Hispanic participants with normal blood pressure from the New York and Los Angeles sites were invited to participate in the substudy MESA Stress 1. In this substudy, researchers analyzed levels of norepinephrine, epinephrine, dopamine and cortisol – hormones that respond to stress levels. Hormone levels were measured in a 12-hour overnight urine test. The substudy included 412 adults ages 48 to 87 years. About half were female, 54% were Hispanic, 22% were Black and 24% were white.

Participants were followed for three more visits (between September 2005 and June 2018) for development of hypertension and cardiovascular events such as chest pain, the need for an artery-opening procedure, or having a heart attack or stroke.

Norepinephrine, epinephrine and dopamine are molecules known as catecholamines that maintain stability throughout the autonomic nervous system—the system that regulates involuntary body functions such as heart rate, blood pressure and breathing. Cortisol is a steroid hormone released when one experiences stress and is regulated by the hypothalamic-pituitary-adrenal axis, which modulates stress response.

“Although all of these hormones are produced in the adrenal gland, they have different roles and mechanisms to influence the cardiovascular system, so it is important to study their relationship with hypertension and cardiovascular events, individually,” Inoue said.

Their analysis of the relationship between stress hormones and development of atherosclerosis found:

  • Over a median of 6.5-year follow-up period, every time the levels of the four stress hormones doubled was associated with a 21-31% increase in the risk of developing hypertension.
  • During a median of 11.2-years of follow-up, there was a 90% increased risk of cardiovascular events with each doubling of cortisol levels. There was no association between cardiovascular events and catecholamines.

“It is challenging to study psychosocial stress since it is personal, and its impact varies for each individual. In this research, we used a noninvasive measure — a single urine test — to determine whether such stress might help identify people in need of additional screening to prevent hypertension and possibly cardiovascular events,” Inoue said.

“The next key research question is whether and in which populations increased testing of stress hormones could be helpful. Currently, these hormones are measured only when hypertension with an underlying cause or other related diseases are suspected. However, if additional screening could help prevent hypertension and cardiovascular events, we may want to measure these hormone levels more frequently.”

A limitation of the study is that it did not include people who had hypertension at the study’s start, which would have resulted in a larger study population. Another limitation is that researchers measured stress hormones via a urine test only, and no other tests for stress hormone measurement were used.

Source: American Heart Association

Autumn Marbled Terrine

Ingredients

1 Savoy cabbage
2 boneless, skinless free-range chicken half-breasts
3 tbsp duck fat
3/4 cup port
5 gelatin sheets
24 sage leaves
10 oz wild mushrooms, wiped or washed and any grit removed
2 smoked duck breasts
toast, for serving
salt
black pepper

Method

  1. Separate the cabbage leaves, discarding the toughest and any that are damaged. Trim out the stalks and wash the leaves well.
  2. Bring a pan of salted water to a boil, add the leaves, and cook until tender. Drain, then refresh the leaves in iced water to stop the cooking, and drain again. Set aside.
  3. Season the chicken.
  4. Heat a tablespoon of the duck fat in a frying pan over high heat and sear the chicken on both sides. Add the port, cover the chicken with a piece of parchment paper, and simmer gently until cooked. Remove the chicken and set aside, keeping the liquid.
  5. Soak the gelatin sheets in a dish of cold water to soften. Remove, squeeze out the excess water and add the softened gelatin to the pan with the port. Stir until it has dissolved, then set aside.
  6. Heat another tablespoon of duck fat in a large pan and add the cabbage leaves. Season with salt and pepper, add the sage, and cook the cabbage until soft. Pour in the port and gelatin mixture.
  7. Melt the remaining tablespoon of duck fat in a frying pan and saute the mushrooms until tender. Season and set aside.
  8. Remove the skin from the smoked duck breasts and cut them into fine strips.
  9. Line the terrine dish with plastic wrap and place a layer of port-soaked cabbage in the bottom. Now add a layer of mushrooms, more cabbage, then chicken, mushrooms, duck, cabbage, and mushrooms. Finish with a layer of cabbage leaves.
  10. Wrap the plastic wrap tightly over the top and add a weight on top to press the terrine down. Place the dish in the fridge overnight to set.
  11. The next day, use the plastic wrap to help you lift the terrine carefully out of the dish. Slice and eat with toast.

Makes 12 servings.

Source: The French Kitchen


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