Nancy Lapid

(Reuters) – The following summarizes recent research on COVID-19. These include additional research to confirm the findings, and which has not yet been certified by peer review.

Brute infections might be less contagious

A small South Korean study suggests that fully vaccinated people infected by the coronavirus are less likely to spread it to others and stay contagious longer than those who have been partially or completely vaccinated.

Researchers found that COVID-19 was transmitted by 77% of vaccinated hospital workers to COVID-19 in breakthrough cases. This is despite the fact that both groups were carrying similar levels of virus load at the time. Researchers observed infectious virus particles being shed in 45 patients with mild COVID-19, who were also being monitored. The researchers found that the virus was present in six of the 60 people who had received full vaccinations, eight days in those who had only been partially vaccinated and ten days in those who hadn’t. All of the infections were acquired before the Omicron variant was circulating, the researchers noted on Tuesday in JAMA Network Open https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2792598.

The researchers stated, “Data from this research provide significant evidence that COVID-19 immunizations continue to be critically effective for controlling SARS CoV-2.”

Cancer patients are more likely to be vaccinated.

COVID-19 vaccines work in almost all cancer patients but are less effective than the general population. The effectiveness also wanes faster, as shown in a large clinical study.

Researchers tracked more than 377,194 patients with cancer, and 28 million others without any malignancies, when the Delta coronavirus variant was dominant in the UK. After two doses of a COVID-19 vaccine from Pfizer/BioNTech or AstraZeneca (NASDAQ:), overall vaccine effectiveness against infection was 69.8% in the general population and only slightly lower, at 65.5%, for cancer patients, the researchers reported on Monday in The Lancet Oncology https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(22)00202-9/fulltext. Three to six months later vaccine effectiveness had fallen to 47% for the cancer patients, while it was at 61.4% for the general population. Researchers found that vaccines proved 83.3% to be effective in COVID-related hospitalizations and 93.4% against cancer deaths. However, this protection also decreased within three to six months. People with leukemia or lymphoma were the most susceptible to vaccine failure and their effectiveness decreased rapidly. Patients with cancer who received radiotherapy or chemotherapy within the past twelve months had a lower vaccine efficacy and their effectiveness waned quicker than patients who were not treated in that time period.

Peter Johnson, University of Southampton’s study leader said that the study “underlines the importance of vaccine booster programs and quick access to COVID-19 treatment for patients undergoing chemotherapy.”

MRI techniques may give clues about long COVID breathlessness

A small study has shown that magnetic resonance imaging (MRI), a specific type of imaging, can detect lung abnormalities in people suffering from persistent breathlessness following COVID-19.

Researchers performed HpXeMRI on 23 shortness-of-breath patients who suffered from severe symptoms for up to three months, 11 of whom did not require hospitalization. The goal was to detect abnormalities or gas exchange. That is the movement of oxygen and carbon dioxide between the lungs, blood, and tissues. All participants had normal or near normal CT scans and lung function tests, but in both groups, Hp-XeMRI showed abnormalities in gas transfer, the research team reported on Tuesday in Radiology https://pubs.rsna.org/doi/full/10.1148/radiol.220069. These abnormalities can’t be explained, nor do they know if the abnormalities contribute to patient symptoms. The most frequent symptoms of long-term COVID are shortness and difficulty breathing. Researchers hope that the results from this study can help them to determine the source.

James Grist, a University of Oxford study coauthor said that Hp-XeMRI could help us understand why long-term COVID patients experience breathlessness. This will allow us to develop better treatment options.

Click for a Reuters graphic https://tmsnrt.rs/3c7R3Bl on vaccines in development.