Tag Archives: Immune System

‘When will it end?’: How a changing virus is reshaping scientists’ views on COVID-19

By Julie Steenhuysen and Kate Kelland

CHICAGO (Reuters) – Chris Murray, a University of Washington disease expert whose projections on COVID-19 infections and deaths are closely followed worldwide, is changing his assumptions about the course of the pandemic.

Murray had until recently been hopeful that the discovery of several effective vaccines could help countries achieve herd immunity, or nearly eliminate transmission through a combination of inoculation and previous infection. But in the last month, data from a vaccine trial in South Africa showed not only that a rapidly-spreading coronavirus variant could dampen the effect of the vaccine, it could also evade natural immunity in people who had been previously infected.

“I couldn’t sleep” after seeing the data, Murray, director of the Seattle-based Institute for Health Metrics and Evaluation, told Reuters. “When will it end?” he asked himself, referring to the pandemic. He is currently updating his model to account for variants’ ability to escape natural immunity and expects to provide new projections as early as this week.

A new consensus is emerging among scientists, according to Reuters interviews with 18 specialists who closely track the pandemic or are working to curb its impact. Many described how the breakthrough late last year of two vaccines with around 95% efficacy against COVID-19 had initially sparked hope that the virus could be largely contained, similar to the way measles has been.

But, they say, data in recent weeks on new variants from South Africa and Brazil has undercut that optimism. They now believe that SARS-CoV-2 will not only remain with us as an endemic virus, continuing to circulate in communities, but will likely cause a significant burden of illness and death for years to come.

As a result, the scientists said, people could expect to continue to take measures such as routine mask-wearing and avoiding crowded places during COVID-19 surges, especially for people at high risk.

Even after vaccination, “I still would want to wear a mask if there was a variant out there,” Dr. Anthony Fauci, chief medical advisor to U.S. President Joe Biden, said in an interview. “All you need is one little flick of a variant (sparking) another surge, and there goes your prediction” about when life gets back to normal.

Some scientists, including Murray, acknowledge that the outlook could improve. The new vaccines, which have been developed at record speed, still appear to prevent hospitalizations and death even when new variants are the cause of infection. Many vaccine developers are working on booster shots and new inoculations that could preserve a high level of efficacy against the variants. And, scientists say there is still much to be learned about the immune system’s ability to combat the virus.

Already, COVID-19 infection rates have declined in many countries since the start of 2021, with some dramatic reductions in severe illness and hospitalizations among the first groups of people to be vaccinated.

WORSE THAN FLU

Murray said if the South African variant, or similar mutants, continue to spread rapidly, the number of COVID-19 cases resulting in hospitalization or death this coming winter could be four times higher than the flu. The rough estimate assumes a 65% effective vaccine given to half of a country’s population. In a worst-case scenario, that could represent as many as 200,000 U.S. deaths related to COVID-19 over the winter period, based on federal government estimates of annual flu fatalities.

His institute’s current forecast, which runs to June 1, assumes there will be an additional 62,000 U.S. deaths and 690,000 global deaths from COVID-19 by that point. The model includes assumptions about vaccination rates as well as the transmissibility of the South African and Brazilian variants.

The shift in thinking among scientists has influenced more cautious government statements about when the pandemic will end. Britain last week said it expects a slow emergence from one of the world’s strictest lockdowns, despite having one of the fastest vaccination drives.

U.S. government predictions of a return to a more normal lifestyle have been repeatedly pushed back, most recently from late summer to Christmas, and then to March 2022. Israel issues “Green Pass” immunity documents to people who have recovered from COVID-19 or been vaccinated, allowing them back into hotels or theaters. The documents are only valid for six months because it’s not clear how long immunity will last.

“What does it mean to be past the emergency phase of this pandemic?,” said Stefan Baral, an epidemiologist at the Johns Hopkins School of Public Health. While some experts have asked whether countries could completely eradicate any case of COVID-19 through vaccines and stringent lockdowns, Baral sees the goals as more modest, but still meaningful. “In my mind, it’s that hospitals aren’t full, the ICUs aren’t full, and people aren’t tragically passing,” he said.

“SCIENTIFIC WHIPLASH”

From the beginning, the new coronavirus has been a moving target.

Early in the pandemic, leading scientists warned that the virus could become endemic and “may never go away,” including Dr. Michael Ryan, head of the World Health Organization’s emergencies program.

Yet they had much to learn, including whether it would be possible to develop a vaccine against the virus and how quickly it would mutate. Would it be more like measles, which can be kept almost entirely at bay in communities with high rates of inoculation, or flu, which infects millions globally each year?

For much of 2020, many scientists were surprised and reassured that the coronavirus had not changed significantly enough to become more transmissible, or deadly.

A major breakthrough came in November. Pfizer Inc and its German partner BioNTech SE as well as Moderna Inc said their vaccines were around 95% effective at preventing COVID-19 in clinical trials, an efficacy rate that is much higher than any flu shot.

At least a few of the scientists Reuters interviewed said even in the wake of those results, they hadn’t expected the vaccines to wipe out the virus. But many told Reuters that the data raised hope within the scientific community that it would be possible to virtually eliminate COVID-19, if only the world could be vaccinated quickly enough.

“We all felt quite optimistic before Christmas with those first vaccines,” said Azra Ghani, chair in infectious disease epidemiology at Imperial College London. “We didn’t necessarily expect such high-efficacy vaccines to be possible in that first generation.”

The optimism proved short-lived. In late December, the UK warned of a new, more transmissible variant that was quickly becoming the dominant form of the coronavirus in the country. Around the same time, researchers learned of the impact of the faster-spreading variants in South Africa and in Brazil.

Phil Dormitzer, a top vaccine scientist at Pfizer, told Reuters in November that the U.S. drugmaker’s vaccine success signaled the virus was “vulnerable to immunization” in what he called “a breakthrough for humanity.” By early January, he acknowledged the variants heralded “a new chapter” in which companies will have to constantly monitor for mutations that could dampen the effect of vaccines.

In late January, the impact on vaccines became even clearer. Novavax’s clinical trial data showed its vaccine was 89% effective in a UK trial, but just 50% effective at preventing COVID-19 in South Africa. That was followed a week later by data showing the AstraZeneca PLC vaccine offered only limited protection from mild disease against the South African variant.

The most recent change of heart was considerable, several of the scientists told Reuters. Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego, described it as “scientific whiplash”: In December, he had believed it was plausible to achieve so-called “functional eradication” of the coronavirus, similar to measles.

Now, “getting as many people vaccinated as possible is still the same answer and the same path forward as it was on December 1 or January 1,” Crotty said, “but the expected outcome isn’t the same.”

(Reporting by Julie Steenhuysen in Chicago and Kate Kelland in London; additional reporting by Michael Erman in New York; Editing by Michele Gershberg and Cassell Bryan-Low)

Immune system can cause broad damage in COVID-19; dogs can detect coronavirus in people

By Nancy Lapid

(Reuters) – The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Immune system can self-attack broadly in COVID-19

Antibodies are supposed to attack invading germs, but severely ill COVID-19 patients have so-called autoantibodies that mistakenly attack not just their own tissues and organs but even virus-fighting proteins produced by the immune system, new research shows. Scientists studied 194 COVID-19 patients, including 55 with severe disease, plus a control group of 30 people without the virus. In the sickest patients, they found a high frequency of autoantibodies created by the immune system causing injury to the central nervous system, blood vessels, and connective tissues like cartilage, ligaments and tendons. They also found a high prevalence of autoantibodies that interfere with substances involved in the functioning of the immune system itself, including cytokines and other “immunomodulatory” proteins. “The surprising extent of autoantibody reactivities” in these patients indicates that these mistakenly targeted antibodies are “an intrinsic aspect” of COVID-19. The report was posted on medRxiv on Saturday ahead of peer review.

Dogs can sniff out COVID-19

Trained dogs can identify people with COVID-19, even those with no symptoms, according to researchers. In the preliminary study published on Thursday in PLoS One, dogs who sniffed swab samples of armpit sweat could tell which samples came from COVID-19 patients and which were from people who tested negative for the new coronavirus. That study was conducted in March. More recently, the researchers have validated the findings in additional trials, said study leader Dominique Grandjean of Alfort Veterinary School in France. Dogs can identify infected individuals with 85% to 100% accuracy and rule out infection with 92% to 99% accuracy, Grandjean said. “It takes one tenth of a second for a trained dog to say ‘yes’ or ‘no’,” he said. Training requires 3 to 8 weeks depending on whether the dog is already trained for odor detection. COVID-19-detecting dogs have already been deployed in airports in the United Arab Emirates, Grandjean said. On Wednesday, the UAE and the International K9 Working Group Against COVID-19 will host a virtual workshop on the use of these trained dogs, with 25 countries expected to participate, according to the organizers.

COVID-19 not linked with Guillain-Barré syndrome

COVID-19 is not associated with the potentially paralyzing disorder Guillain-Barré syndrome (GBS), a large UK study shows. In GBS, the immune system mistakenly attacks nerves in the feet, hands and limbs. Smaller studies have suggested a link between COVID-19 and GBS. But when researchers compared the number of GBS cases recorded in the UK’s National Health Service database in 2016 to 2019 to the number recorded in the first half of 2020, they found the annual incidence was 40% to 50% lower during the pandemic. “No causal link of COVID-19 to GBS can be made,” Stephen Keddie of University College London said in a statement. His team reported on Monday in the journal Brain that they also looked for – but could not find – any genetic or protein structure in the new coronavirus that might trigger an immune response causing GBS, which is good news for vaccine development. “Most COVID-19 vaccinations are based on the (coronavirus’) spike protein, which drives a complex immune response creating antibodies to fight infection,” Keddie said. Since researchers found nothing in the virus that is known to drive GBS, “concerns that COVID vaccination might cause GBS in any significant numbers are therefore almost certainly unfounded,” he said.

Antibiotic azithromycin fails to help in severe COVID-19

The antibiotic azithromycin failed to help seriously ill adults infected with the new coronavirus, according to results from a clinical trial. Based on the result, the only COVID-19 patients who should get the antibiotic are those who also have bacterial infections, the study leaders said. The trial, conducted at 176 hospitals across the UK, involved more than 9,000 patients and tested multiple drugs to see if any would be more effective than standard hospital care in treating COVID-19. According to preliminary data published on Monday on medRxiv ahead of peer review, patients who were randomly assigned to receive azithromycin did no better than patients who got standard care in terms of deaths, duration of hospitalization, or need for mechanical ventilation. “More than 75% of hospitalized COVID-19 patients are prescribed antibiotics,” the researchers point out. “Although we detected no harm to individual patients treated with azithromycin, there is a risk of harm at a societal level from widespread use of antimicrobial agents,” researchers said. The widespread use of antibiotics in COVID-19 patients “in general must be questioned,” they concluded.

(Reporting by Nancy Lapid; Editing by Bill Berkrot)

NIH tests therapies to help cut hospital stays for COVID-19 patients

(Reuters) – The U.S. National Institutes of Health (NIH) has started a late-stage trial to evaluate if immune-modulating therapies from three drugmakers can help reduce the need for ventilators for COVID-19 patients and shorten their hospital stay.

The NIH said on Friday it has selected three agents for the study – Johnson & Johnson unit Janssen Research’s Remicade, Bristol Myers Squibb’s Orencia and Abbvie Inc’s experimental drug cenicriviroc.

The study will enroll up to 2,100 hospitalized adults with moderate to severe COVID-19 symptoms in the United States and Latin America.

Immune-modulating therapies are medications that alter the way the immune system works. Severe infections are believed to be triggered by an over-reaction of the immune system, known as a “cytokine storm,” and drugs that suppress certain elements of the immune system can play a role in arresting a rapid escalation of symptoms.

This can lead to acute respiratory distress syndrome and multiple organ failure, among other life-threatening complications.

The NIH said its clinical trial – ACTIV-1 Immune Modulators (IM) – will last six months, and the agency will study if the therapeutics can restore balance by modulating that immune response.

All patients will be given Gilead Sciences Inc’s antiviral drug remdesivir – the current standard of care – and also be randomly assigned to receive a placebo or one of the immune modulators as an add-on treatment, the NIH said in a statement.

Remdesivir was one of the drugs used to treat U.S. President Donald Trump’s coronavirus infection, and has been shown in previous studies to have cut time to recovery, though the European Union is investigating it for possible kidney injury.

(Reporting by Vishwadha Chander in Bengaluru, Editing by Sherry Jacob-Phillips)

Convalescent plasma lowers COVID-19 death risk; exposure to common cold may limit disease severity

By Nancy Lapid

(Reuters) – The following is a brief roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Convalescent plasma lowers COVID-19 death risk

Infusions of antibody-rich blood plasma from people who have recovered from the new coronavirus, known as convalescent plasma, can lower the risk of death for hospitalized COVID-19 patients, according to a pooled analysis of data from eight earlier studies of more than 700 hospitalized patients around the world. Researchers found that mortality rates were roughly 13% in patients who received convalescent plasma versus about 25% for those who did not get the treatment. Convalescent plasma was shown to be safe in an earlier study of 5,000 hospitalized adults with severe or life-threatening COVID-19. In that study, fewer than 1% of patients had any serious adverse effects in the first four hours after transfusion. The current study could not account for differences in factors such as how sick patients were, how much plasma they received, how long they were sick before the received it, and how long doctors followed them afterward. “Given the safety of plasma administration in COVID-19 patients, the results … provide encouragement for its continued used as a therapy,” the researchers write in a report published ahead of peer review.

Exposure to common colds may impact COVID-19 severity

In patients with COVID-19, the immune system’s T cells learn to recognize and target the new coronavirus. But some people who were never infected with the virus nonetheless have T cells that also recognize it. Researchers had suspected that in these individuals, past exposure to other corona viruses, such as those that cause the common cold, had somehow primed their T cells to recognize and attack this new coronavirus (SARS-CoV-2), and new research appears to confirm that. In studies of human blood samples collected well before the new coronavirus was discovered, researchers found T cells that were equally reactive against the new virus and four types of common cold corona viruses. The strongest T cell responses to the new coronavirus were associated with the spike protein the virus uses to enter human cells. “We knew there was pre-existing reactivity, and this study provides very strong direct molecular evidence that memory T cells can ‘see’ sequences that are very similar between common cold corona viruses and SARS-CoV-2,” coauthor Alessandro Sette of the La Jolla Institute for Immunology said in a statement. It is plausible to think that previous exposure to common cold viruses might contribute to variations in COVID-19 severity, researchers said on Tuesday in the journal Science.

Severe COVID-19 may be less deadly in children

Children with COVID-19 rarely become critically ill, and when they do, they tend to have better outcomes than adults, based on early data from an ongoing study. The Critical Coronavirus and Kids Epidemiology (CAKE) study involves 65 pediatric intensive care units in 18 countries. In a paper published on Wednesday in the journal Pediatrics, the study team reported on the first 17 children with severe COVID-19 from 10 hospitals in Chile, Colombia, Italy, Spain and the United States. Most required respiratory support, with nearly half needing to be put on ventilators. Symptoms were varied, with fever, cough and gastrointestinal issues common. Overall, one child died, four developed inflammation of the heart and three remain hospitalized. The investigators hope to have more data soon that will provide additional information on the care and outcomes of these patients, which may become more important as schools reopen around the world. As of now, CAKE has enrolled almost 100 critically ill children “and we are projecting perhaps 100 more by the end of 2020,” Dr. Sebastian Gonzalez-Dambrauskas, with the Latin American Pediatric Collaborative Network, told Reuters.

(Reporting by Nancy Lapid and Megan Brooks; Editing by Bill Berkrot)

Fasting For Two Days Can Boost Immune System

A new study from the University of Southern California shows fasting for as little as two days can regenerate the body’s immune system.

The study showed that fasting worked not only for normal, “healthy” people but also the elderly and people whose immune systems have been compromised because of chemotherapy treatments.

The periods without eating would lower the amount of white blood cells in the body, which would trigger stem cells to begin regeneration of the white blood cells, rushing them into the body.  However, the scientists also found that the rush of white blood cells also repaired damage.

“[Fasting] gives the OK for stem cells to go ahead and being proliferating and rebuild the entire system,” Professor Valter Longo said.  “And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting.”

A pilot clinical trial found that fasting for 72 hours prior to chemotherapy protected the patients against toxicity.