Strong immune response from J&J vaccine; antibodies found in pets
THIS WEEK’S roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments brings good news. The experimental vaccine developed by Johnson & Johnson has shown positive results in clinical trials while French researchers have discovered antibodies in the pets of people who have had COVID-19.
POSITIVE RESULTS FOR J&J VACCINE
A single dose of Johnson & Johnson’s experimental COVID-19 vaccine produced a strong immune response against the novel coronavirus, according to interim results from an early-to-mid stage clinical trial released Friday.
The study, backed by the U.S. government, involves about 1,000 adults. The results were published on the medical website medRxiv in advance of peer review.
Of the several hundred participants with data available for the interim analysis, the results showed that 98% had neutralizing antibodies, which defend cells from pathogens, 29 days after vaccination. However, immune response results were available from only 15 participants over age 65, leaving open the question of whether elderly people, one of the populations most at risk, will be protected as effectively as others. In participants older than 65, the rate of adverse reactions such as fatigue and muscle aches was 36%, much lower than the 64% seen in younger participants, the results showed, suggesting the immune response in older people may not be as strong.
The researchers said more details on safety and effectiveness will follow when the study is completed. But there were no serious side effects, and based on the results so far, J&J kicked off a 60,000-person trial of the vaccine Wednesday. A single shot, versus a rival two-dose approach being tested by Moderna Inc. and Pfizer Inc., could simplify the distribution of the vaccine.
ONLY 1 IN 5 REMAIN ASYMPTOMATIC
Most people infected with the new coronavirus will have symptoms, according to researchers who reviewed data from nearly 80 studies of individuals with positive PCR tests for COVID-19. Overall, just 20% remained asymptomatic. Five of the studies provided enough data for the researchers to examine the spread of the disease.
Compared to COVID-19 patients with symptoms, patients who never developed symptoms were 65% less likely to transmit the virus to others, the researchers reported on Tuesday in the journal PloS Medicine.
“A minority of people has truly asymptomatic SARS-CoV-2 infection and, if they are less infectious than people with symptoms, they probably account for a relatively small proportion of all transmission,” coauthor Dr. Nicola Low of the University of Bern told Reuters.
“Most people will go on to develop symptoms and there is a substantial amount of transmission during the pre-symptomatic phase,” Low said. That means prevention measures to reduce transmission, including face covering, social distancing, physical barriers and widespread testing and contact tracing to find and isolate contagious people remains necessary.
ANTIBODIES IN PATIENTS’ PETS
Living with a human who has COVID-19 raises the risk that dogs and cats will be infected with the new coronavirus, according to a French study.
Blood tests performed on 34 cats and 13 dogs belonging to patients who had recovered from COVID-19 found antibodies to the virus, indicating likely past infection, in 21% of the pets – 8 cats and 2 dogs. By comparison, among 38 pets in households with no known COVID-19, only one cat tested positive, according to a report of the study posted on bioRxiv ahead of peer review.
“We cannot definitively prove that all the 10 positive animals were infected with SARS-CoV-2,” the authors said, adding that it is not known whether infected pets can spread the virus back to humans. “While viral shedding from pets does not appear sufficient for transmission to humans or other animals encountered during walks, for people in closer contact, precautionary measures should be considered.”