This week's roundup of some of the latest scientific studies on the coronavirus and efforts to find treatments and vaccines for COVID-19 reveals concerning information about new coronavirus variants, addresses solutions for a lingering symptom and gives inoculation advice for cancer patients.

Cancer patients should get vaccinated

Patients with active cancers, as well as those in remission, face a significantly higher risk of severe COVID-19, according to a new study.

Researchers analyzed medical records from 4,816 patients who had been tested for the virus, including 323 with a history of cancer. Cancer patients had more than twice the odds of being hospitalized for COVID-19 and more than five times the risk of dying from the disease, compared with people without a cancer history, researchers reported in JNCI Cancer Spectrum. The extra risks were more pronounced for people whose cancers were not in remission.

The findings underscore the importance of social distancing, mask-wearing and hand washing for cancer patients, including those in remission, the researchers said. The U.S. National Comprehensive Cancer Network said that everyone being treated for cancer should be prioritized for vaccination, and their caregivers and other members of the same household should get vaccinated as soon they become eligible.

Virus variant found in California drives SoCal surge

A new variant of the coronavirus appears to account for the recent surge of cases in southern California, researchers say. The variant, called CAL.20C, accounted for fewer than one in every 1,000 COVID-19 cases in Los Angeles County in July. It was not detected again until October, but by December accounted for 36% of cases, researchers from Cedars-Sinai Medical Center in Los Angeles reported on medRxiv ahead of peer review.

The CAL.20C variant is distinct from those discovered in the U.K., South Africa and Brazil. It carries five mutations: three in the spike protein, which the virus uses to break into cells, and two in other parts of the virus. CAL.20C has also been detected in northern California, New York and Washington, D.C. Whether it is more easily transmissible or resistant to antibodies than earlier versions of the virus is not yet known.

The researchers intend to "mine the data and see how patients do over time," coauthor Jasmine Plummer said. The proliferation of CAL.20C in November and December shows that "we allowed it to emerge during the holidays," she said. "These kind of numbers reinforce that we need to wear masks, socially isolate and stay home."

South African variant may resist current antibody treatments

The variant of the coronavirus identified in South Africa can resist, or "escape," antibodies that neutralize earlier versions of the virus, scientists have found. It "exhibits complete escape" from three classes of monoclonal antibodies manufactured for treating COVID-19 patients, and it shows "substantial or complete" resistance to neutralizing antibodies in blood donated by COVID-19 survivors, the scientists reported on bioRxiv ahead of peer review.

Similarities between the South Africa variant and another variant identified in Brazil suggest the Brazilian variant will show similar resistance, they added. Liam Smeeth of the London School of Hygiene and Tropical Medicine, who was not involved in the study, noted that these were laboratory tests, and it would be unwise to extrapolate the findings to humans at this point.

"The data do raise the possibility that the protection gained from past infection with COVID-19 may be lower for reinfection with the South African variant," he said. "The data also suggest that the existing vaccines could be less effective against the South African variant." He called for large studies among populations where the variant is common.

'Smell training' advised for lingering smell problems

COVID-19 survivors whose sense of smell does not return to normal should receive a form of "smell rehab" known as olfactory training, experts advise. Olfactory impairment, or trouble smelling things, is a common after-effect of many types of infections.

"Patients with COVID-19 and other infection-related olfactory dysfunction should be guided through olfactory rehabilitation" and should be referred to specialists for other treatments if the training does not help, a panel of experts recommends in a paper published in the Journal of Allergy and Clinical Immunology.

Olfactory training involves sniffing four specific scents (for example, lemon, rose, cloves and eucalyptus) for five minutes twice a day for at least three months. With a sense of smell problems estimated to affect over 60% of people infected with the new coronavirus, doctors in the U.K. have made available a free online smell training program called NoseWell, which people can use to try to regain their sense of smell.