The following is a summary of some recent studies on Covid-19. They include research that warrants further study to corroborate the findings and that have yet to be certified by peer review.
Severe Covid-19 may "trip off" immune self-attacks
Severe Covid-19 may trick the immune system into producing so-called autoantibodies that have the potential to eventually attack healthy tissue and cause inflammatory diseases, researchers warned in a paper published in Nature Communications.
They found autoantibodies in blood samples from roughly 50 per cent of 147 Covid-19 patients they studied but in fewer than 15 per cent of 41 healthy volunteers.
For 48 Covid-19 patients, the researchers had blood samples taken over different days, including the day of hospital admission, allowing them to track the development of the autoantibodies.
"Within a week... about 20 per cent of these patients had developed new antibodies to their own tissues that weren't there the day they were admitted," study leader Dr Paul Utz of Stanford University said in a news release.
He urged people to get vaccinated. "You can't know in advance that when you get Covid-19 it will be a mild case," he said. "If you do get a bad case, you could be setting yourself up for a lifetime of trouble because the virus may trip off autoimmunity," he said.
"We haven't studied any patients long enough to know whether these autoantibodies are still there a year or two later," he added, but noted that developing an autoimmune disease was a possibility.
New variants may spread more efficiently into the air
The virus that causes Covid-19 may be getting better at travelling into the air, a new study suggests.
Researchers found that patients infected with the Alpha variant of the virus - the dominant strain circulating when the study was conducted - put 43 to 100 times more virus into the air than people infected with the original version of the coronavirus.
Some of this was due to the fact that patients infected with Alpha had increased amounts of virus in nasal swabs and saliva.
But the amount of virus being exhaled was 18 times more than could be explained by the higher viral loads, according to a report published in Clinical Infectious Diseases.
The researchers also found that loose-fitting face coverings worn by patients with mild Covid-19 can reduce the amount of virus-laden particles in the surrounding air around by about 50 per cent.
"We know that the Delta variant circulating now is even more contagious than the Alpha variant," coauthor Don Milton of the University of Maryland School of Public Health said in a statement.
"Our research indicates that the variants just keep getting better at travelling through the air, so we must provide better ventilation and wear tight-fitting masks, in addition to vaccination, to help stop the spread of the virus."
Most cancer patients respond well to Covid-19 vaccines
People with cancer have appropriate, protective immune responses to Covid-19 vaccines without experiencing any more side effects than the general population, five separate research teams reported at the European oncology meeting this week.
In one study involving 44,000 recipients of the two-dose Pfizer/BioNTech vaccine, researchers found no difference in side effects experienced by the nearly 4,000 participants with past or current cancer.
In a separate trial, researchers studied 791 cancer patients who received the two-dose vaccine from Moderna.
At 28 days after administration of the second dose, adequate levels of antibodies to the virus in the blood were found in 84 per cent of patients with cancer who were receiving chemotherapy, in 89 per cent of patients receiving chemotherapy plus an immunotherapy drug, and in 93 per cent of patients on immunotherapy alone.
These results compare favourably with the antibody responses seen in a separate group of individuals without cancer, according to European Society for Medical Oncology (ESMO) Press Officer Dr Antonio Passaro.
"The high rates of the efficacy of the vaccine observed across the trial population, regardless of the type of anticancer treatment, constitute a strong and reassuring message for patients and their doctors," he said in a statement.