Tag Archives: immune cells

India COVID-19 variant exhibits resistance; antibody drug shows promise

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.

India variant shows resistance to antibody drugs, vaccines

Antibody drugs and COVID-19 vaccines are less effective against a coronavirus variant that was first detected in India, according to researchers. The variant, known as B.1.617.2, has mutations that make it more transmissible. It is now predominant in some parts of India and has spread to many other countries. A multicenter team of scientists in France studied a B.1.617.2 variant isolated from a traveler returning from India. Compared to the B.1.1.7 variant first identified in Britain, the India variant was more resistant to antibody drugs, although three currently approved drugs still remained effective against it, they found. Antibodies in blood from unvaccinated COVID-19 survivors and from people who received both doses of the Pfizer/BioNTech vaccine were 3-fold to 6-fold less potent against the India variant than against the UK variant and a variant first identified in South Africa, according to a report posted on Thursday on the website bioRxiv ahead of peer review. The two-dose AstraZeneca vaccine, which does not protect against the South Africa variant, is likely to be ineffective against the India variant as well. Antibodies from people who had received their first dose “barely inhibited” this India variant, said study co-author Olivier Schwartz of Institut Pasteur. The study, Schwartz added, shows that the rapid spread of the India variant is associated with its ability to “escape” the effect of neutralizing antibodies.

New antibody drug keeps mild COVID-19 from worsening

An antibody drug from Vir Biotechnology and GlaxoSmithKline that protects against progression of COVID-19 in high-risk patients with mild to moderate disease received emergency use authorization by the U.S. Food and Drug Administration on Wednesday. In a large randomized trial, patient risk of progression to more severe illness was reduced by 85% with the drug, sotrovimab, compared to a placebo, according to an interim report from the trial posted on Friday on the medRxiv website in advance of peer review. Everyone in the trial had risk factors for severe COVID-19 such as heart disease, diabetes, obesity and old age. Three of 291 patients (1%) in the sotrovimab group became sick enough to be hospitalized, versus 21 of 292 (7%) in the placebo group, researchers said. All five patients who needed to be admitted to intensive care received placebo, they reported. Serious complications were less common with sotrovimab than with placebo, they added. The antibody treatment will be available for COVID-19 patients in the coming weeks, GSK and Vir said on Wednesday.

Joint and muscle disease drugs may limit vaccine response

The COVID-19 vaccines from Pfizer/BioNTech and Moderna may be less effective in patients taking immunosuppressant drugs for rheumatic and musculoskeletal diseases, researchers said. “While additional research is required, patients on immunosuppressants should be aware that they may not be fully protected against COVID even after full vaccination. Therefore, patients should talk to their providers before relaxing precautions,” said Dr. Julie Paik of Johns Hopkins University School of Medicine in Baltimore. In an earlier study, her team found that most patients with rheumatic and musculoskeletal diseases do respond appropriately to the vaccines. Looking more closely at 20 people whose immune systems did not respond well – that is, no antibodies were detectable after vaccination – the researchers found that most were receiving multiple immunosuppressive agents. “A unifying factor” among the patients was their use of medications such as rituximab and mycophenolate mofetil that affect immune cells called lymphocytes that produce antibodies and help control immune responses, the researchers reported on Monday in the journal Annals of Internal Medicine. “Our study highlights the need for physicians and patients to be aware that immunosuppressants may prevent an appropriate vaccine response against SARS-CoV-2,” Paik said.

Robust, coordinated immune response marks mild COVID-19

In COVID-19 patients who do not become seriously ill, the immune system reacts to the virus “robustly,” with a highly coordinated response, and this coordination may be one key to ensuring a mild illness, according to researchers. Detailed studies of immune system behavior in COVID-19 patients have focused primarily on those with moderate or severe illness and have found “uncoordinated” immune responses. The new study, posted Wednesday on the bioRxiv website ahead of peer review, “used cutting-edge methods to deeply study immune cells” in 18 patients with only mild illness, said study co-author Greg Szeto of the Allen Institute for Immunology in Seattle. In these mildly ill volunteers, the more intense the immune response in early infection, the higher the levels of antibodies in their blood after recovery, the multicenter research team found. And compared to participants who recovered, participants who had lingering troublesome symptoms – so-called Long Covid – had weaker immune responses to the virus in early infection, Szeto added. The differences the study found between mildly ill patients who did and did not develop Long Covid may help researchers devise more personalized ways to monitor immune responses to the virus and better methods for treatment, Szeto’s team concluded.

 

(Reporting by Nancy Lapid and Megan Brooks; Editing by Will Dunham)

COVID-19 may damage bone marrow immune cells; another reinfection reported

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.

COVID-19 may damage immune cells in the bone marrow

Even bone marrow may not be a safe harbor from the ravages of COVID-19, according to a study that found previously unrecognized changes in newly produced immune cells, called monocytes, released into the blood from bone marrow. To learn more about how the body responds to COVID-19, researchers obtained serial “snapshots” of patients’ immune health by analyzing their immune cells at multiple points during their hospital stays. In COVID-19 patients with more severe disease, the monocytes do not function properly, researchers reported last week in Science Immunology. It was not yet clear whether the monocytes are being released from the bone marrow in an altered state or whether the alterations happen after monocytes enter the blood, coauthor Tracy Hussell of the University of Manchester in the UK told Reuters. Either way, she said, treatments that prevent their release from the bone marrow may help reduce the exaggerated immune response that contributes to poor outcomes in patients with severe COVID-19.

COVID-19 reinfections occur, but remain rare

Another case of reinfection after recovery from COVID-19 has been reported, this time in a healthy young military healthcare provider at a U.S. Department of Defense hospital in Virginia. He was first infected by a patient in March. He recovered within 10 days and “returned … to excellent health,” his doctors reported on Saturday in Clinical Infectious Diseases. Fifty-one days later, he was reinfected by a household member. Genetic studies showed the first and second infections to be from slightly different strains of the virus. The reinfection made him sicker, perhaps because the second strain was more potent, or the household contact infected him with a higher load of virus, doctors said. It was also possible antibodies from the first infection may have triggered his immune system to respond more strongly to the virus the second time his body encountered it. COVID-19 reinfections are still rare, they said. Kristian Anderson, professor of immunology and microbiology at Scripps Research in La Jolla, California, recently told Reuters virus reinfections are always possible. “We don’t know at what frequency reinfections (with the new coronavirus) occur and how that might change over time,” Anderson said. Without further studies, “we can’t conclude what a single case of reinfection means for longevity and robustness of COVID-19 immunity and relevance for a future vaccine,” she added.

Proven immunotherapy approach might be possible in COVID-19

A proven approach to severe virus infections, known as cytotoxic T cell therapy, may be applicable to COVID-19 despite a potential hurdle, researchers said. The approach involves treating critically ill patients with infusions of key immune cells known as T-lymphocytes obtained from people who successfully fought off the same virus. These donor T cells have learned to recognize and target the invading virus. But steroids, which are being increasingly used to treat COVID-19 patients, are toxic to lymphocytes, likely canceling out any beneficial effects of the immunotherapy. In a new report posted on bioRxiv ahead of peer review, researchers describe a possible workaround. They say they have figured out a way to take donor T cells that target the novel coronavirus and make them resistant to the deadly effects of steroids. “We are currently working on … developing clinical trials to determine safety and efficacy,” coauthor Dr. Katy Rezvani of The University of Texas MD Anderson Cancer Center told Reuters.

High COVID-19 mortality seen in assisted-living facilities

Data compiled from more than 4,600 assisted living facilities in seven U.S. states through the end of May showed a four-fold higher COVID-19 fatality rate than in the nearby communities, researchers reported on Monday in the Journal of the American Geriatric Society. In North Carolina and Connecticut, for example, the proportions of COVID-19 cases that were fatal across the state were 3.3% and 9.3%, respectively. In assisted living facilities in those states, the fatality rate climbed to 13% and 31.6%. Unlike nursing homes, assisted living communities are not subject to federal regulation and are not required to collect and report data on COVID-19, coauthor Helena Temkin-Greener of the University of Rochester School of Medicine & Dentistry said in a news release. In this study, and in a separate study of nursing homes her team published on Monday in the same journal, COVID-19 cases were more common in facilities with more minority residents and more residents with dementia, chronic obstructive pulmonary disease, and obesity. “Assisted living communities and their residents urgently need local, state, and the federal governments to pay at least the same level of attention as that given to nursing homes,” Temkin-Greener and colleagues conclude.

(Reporting by Nancy Lapid and Deena Beasley; Editing by Bill Berkrot)