In this week's roundup, the latest scientific research on the coronavirus and efforts to find treatments and vaccines suggest that immune system memory persists a year after COVID-19, type-2 diabetes risk rises after infection, and antibodies in kids after suffering from the virus last 6 months or more.

Immune system memory persists

A year after infection with the coronavirus, when antibodies in the blood are barely detectable, the immune system continues to "remember" the virus and should respond to some extent upon re-encountering it, a study from China suggests.

Researchers studied 141 people infected with the virus in the first half of 2020 who provided blood samples 12 months later. None of them had been vaccinated in the interim. Most individuals still had low levels of antibodies, and most of those younger than 60 still had some antibodies that could neutralize the virus, according to a report published on Wednesday in The Lancet Microbe.

However, in everyone – regardless of age or severity of the original infection, and including patients who had lost their neutralizing antibodies – responses by so-called memory B cells and memory T-cells were still evident "and were not disrupted by new variants," the researchers said. These defenses do not prevent infection but they do help to prevent severe disease.

"Current SARS-CoV-2 vaccines are mainly focused on neutralizing antibodies," the researchers noted. "These data underline the importance of broad B-cell and T-cell immunity for future vaccine strategies targeting SARS-CoV-2."

Type-2 diabetes risk rises

People may be at increased risk for developing diabetes for up to a year after a diagnosis of COVID-19, according to two studies.

One study used data from the U.S. Department of Veterans Affairs to track more than 181,000 adults with COVID-19 for a year after recovery. Comparing these patients to more than 8 million people not infected with the coronavirus, researchers found that among every 1,000 people, there were 13 more new cases of diabetes among the COVID-19 patients after 12 months than among the uninfected individuals.

The COVID-19 group also had an extra 12 people per thousand who started taking medication for diabetes. Overall, two of every 100 people with COVID-19 developed diabetes in the year afterward, Ziyad Al-Aly of the VA St. Louis Health Care System said on Twitter.

After accounting for other risk factors, including how often subjects in both groups saw their doctors, that translated to a 40% higher risk after COVID-19, his team reported on Monday in The Lancet Diabetes & Endocrinology.

The higher risk for diabetes was evident even in people who had mild or asymptomatic COVID-19 and even in people who did not have any other risk factors for diabetes, Al-Aly told Reuters.

In a separate study of 35,865 people with COVID-19 published last week in Diabetologia, researchers found a 28% higher risk of developing diabetes compared to a group with non-COVID upper respiratory infections.

Nearly all new cases in both studies were type-2 diabetes, which can sometimes be controlled by weight loss and diet changes. The authors all recommend that COVID-19 survivors with symptoms of diabetes, such as excessive thirst or frequent urination should seek medical attention.

Antibodies in kids last 6 months

Most children and adolescents with COVID-19 antibodies after SARS-CoV-2 infection usually still have the antibodies in their blood more than half a year later, new data shows.

Starting in October 2020, researchers in Texas recruited 218 subjects between the ages of 5 and 19. Each provided three blood samples, at three-month intervals. More than 90% were unvaccinated when they enrolled in the study.

The first blood test showed infection-related antibodies indicating recovery from COVID-19 in one-third of the children, the researchers reported online Friday in Pediatrics. Six months later, 96% of those with the antibodies still had them.

The study was designed to detect the presence of antibodies, which are only one component of the immune system's defenses, not the amount of antibodies. The level of protection even in those with antibodies is unclear. Researchers found no differences based on whether a child was asymptomatic, severity of symptoms, when they had the virus or due to weight or gender.

"It was the same for everyone," Sarah Messiah of UTHealth School of Public Health Dallas, said in a statement. "Some parents ... think just because their child has had COVID-19, they are now protected and don't need to get the vaccine," Messiah said. "We have a great tool available to give children additional protection by getting their vaccine."

A small study published earlier this month in JAMA Network Open suggested that most children infected with the coronavirus do not have antibodies in their blood afterward. Only 37% of children appeared to develop antibodies, compared to 76% of adults, even though viral loads were similar in the two groups, those researchers found.