(Reuters) - 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.

Possible "missing link" found in virus reproduction cycle.

Researchers may have found a missing link in the coronavirus reproduction cycle that could potentially be targeted by drugs, according to a report in Science on Thursday.

Two new studies found that people who had received vaccines for other viruses developed fewer or less serious coronavirus infections, though more research is needed to determine their potential effectiveness against COVID-19.

According to a study published in Cell Reports Medicine on Wednesday, people who received the BCG tuberculosis vaccine in the last 3 years did not developed more severe coronavirus infections.

A separate study from the Mayo Clinic, posted online ahead of peer review, found that people who received other vaccines in the past 5 years - such as against flu, pneumonia, or hepatitis - had lower coronavirus infection rates.

Viral loads high in patients without symptoms.

Asymptomatic COVID-19 patients can carry high loads of the new coronavirus in their nose, throat and lungs, and the loads tend to decrease more slowly than in patients who show symptoms, according to a report in JAMA Internal Medicine on Thursday.

Multiple tests over the course of about a month showed similar viral loads in people with or without symptoms.