Patient's antibodies target Covid-19 from multiple angles; children may also suffer from 'long Covid', studies reveal

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.

Long-lasting Covid-19 effects seen in children

"Long Covid" - a term that refers to effects of the virus that linger for weeks or months - may be a problem for children, too, a small study suggests. Doctors at a large Italian hospital tracked 129 children and teens with Covid-19 who were otherwise generally healthy. At an average of about five months after their diagnosis, only about 42% had completely recovered.

Roughly one in three youngsters still had one or two symptoms and more than one in five had three or more, according to a report posted on Tuesday on medRxiv ahead of peer review.

The most common persistent problems were insomnia (reported by 18.6%), respiratory symptoms including pain and chest tightness (14.7%), nasal congestion (12.4%), fatigue (10.8%), muscle pain (10.1%), joint pain (6.9%), and concentration difficulties (10.1%).

Read | Time to team up and tackle 'Long Covid', says WHO expert

Although these issues were more common in children who had been obviously sick, they also developed in infected youths with few or no symptoms initially. There is increasing evidence that restrictive measures aimed at curbing the pandemic are significantly impacting children's' mental health, the researchers acknowledge.

Still, their findings suggest, the potential long-term effects Covid-19 can have on children should be considered when developing measures to reduce the impact of the pandemic on their overall health.

Patients' antibodies target virus from many angles

Most antibody treatments and vaccines targeting the coronavirus focus on stimulating an immune response against the spike protein it uses to break into cells. Targeting other sites on the virus as well may be a better approach, researchers say.

Their study of Covid-19 survivors whose immune systems had generated strong responses to the virus showed that more than half of those antibodies targeted components of the virus other than the spike protein.

The most common non-spike targets of the antibodies were the closed capsule in which the virus stores its genetic instructions and specific segments of those instructions, such as stretches of its RNA code.

This suggests that non-spike related antibodies may play a significant role in clearing the virus, the research team said in a paper posted on Thursday on bioRxiv ahead of peer review. In terms of natural immunity, it also suggests that when faced with new spike protein variants, the immune system will have other sites on the virus that it can still remember and attack.

A spokesperson for the researchers said their company, Immunome Inc, is developing a cocktail of antibodies that target multiple sites on the virus.

Covid-19 may affect kidney filtering

Covid-19 impairs the kidneys' ability to filter waste and toxic substances in some patients, a new report suggests. Kidney filters do not usually allow much protein into the urine.

Researchers who studied 103 Covid-19 patients found that about 24% of them had high levels of the protein albumin in their urine, and 21% had high levels of the protein cystatin c in their urine. About 25% of the patients had a noninfectious piece of the coronavirus in their urine, but none of the samples contained infectious virus.

That suggests the virus particles researchers did see were "a direct result of a filtration abnormality rather than a viral infection of the kidney," according to a report posted on Sunday on medRxiv ahead of peer review.

None of the patients had signs of kidney dysfunction, other than the filtration issues. "At this stage, we do not know whether or not these abnormalities are a sign of long-term consequences," said coauthor Choukri Ben Mamoun of the Yale School of Medicine.

"It is for this reason that we report these findings and emphasize the need for long-term examination of the consequences of this infection."