A 2015 paper on a chicken virus showed vaccines could enable more deadly variants to spread—in chickens. But that outcome is rare. Only a minority of human and animal vaccines have affected the evolution of a virus. In most of those cases, evolution didn’t increase the severity of the pathogen….
Vaccines effective even without post-shot symptoms or prior infection
Vaccination with the two messenger RNA (mRNA) vaccines for SARS-CoV-2, the virus that causes COVID-19, yields a robust antibody response, even if a person did not develop significant symptoms following vaccination or did not have a prior SARS-CoV-2 infection. That’s the key finding from a recent study of nearly 1,000…
Study: Vaccines still effective against delta variant
Obtaining two vaccine doses remains the most effective way to ensure protection against the COVID-19 delta variant of concern dominant in the UK today, according to a study from the University of Oxford. Conducted in partnership with the Office of National Statistics (ONS) and the Department for Health and Social…
Effectiveness of mRNA vaccines against the COVID-19 Alpha and Beta variants in France
Over the past six months, the World Health Organization has categorized four SARS-CoV-2 variants as being “of concern” because they are more transmissible or may escape the immune response. They have been termed the Alpha, Beta, Gamma and Delta variants. Scientists from the Institut Pasteur, in collaboration with the French…
How well do COVID vaccines work in the real world?
Many Australians will be weighing up whether to be vaccinated with the AstraZeneca vaccine, which is widely available, or to wait for Pfizer later in the year. There are many factors to consider. One is how well these COVID-19 vaccines work in the “real world” of those getting vaccines now….
COVID-19 vaccines reduce viral load, severity in breakthrough cases, studies find
Mixed messages from WHO, CDC on mask-wearing as Delta variant spreads The World Health Organization urges fully-vaccinated Americans to wear masks indoors in public places as a precaution as the Centers for Disease Control and Prevention sticks to its eased COVID guidance; Bryan Llenas has the details. Fully vaccinated individuals…
Mandatory COVID vaccines for aged- and health-care workers could increase uptake, but it’s not the first option
Federal Health Minister Greg Hunt has asked the Australian Health Protection Principal Committee to revisit whether COVID vaccinations should be mandatory for aged-care workers and provide fresh advice to national cabinet. In January, the committee said aged-care workers should be “strongly encouraged” to get vaccinated, but given there was little…
mRNA vaccines effective for preventing symptomatic COVID-19
For health care personnel (HCP), the vaccine effectiveness (VE) of authorized mRNA COVID-19 vaccines (Pfizer-BioNTech and Moderna) against symptomatic COVID-19 illness is 82 and 94 percent for a single dose and for two doses, respectively, according to research published in the May 14 early-release issue of the U.S. Centers for…
EU to have enough vaccines for 70% of adults ‘in July’
The EU coronavirus vaccine program will secure enough doses to immunize 70 percent of adults by the end of July, European Commission chief Ursula von der Leyen said Friday. The EU chief had previously set a goal of late September for this feat, but announced the new target during a…
China’s Sinovac Vaccine 67% Effective for Symptomatic Infection
SANTIAGO (Reuters) – Sinovac’s COVID-19 vaccine CoronaVac was 67% effective in preventing symptomatic infection in the first real-world study of the Chinese shot, the Chilean government said on Friday. The vaccine was 85% effective in preventing hospitalizations and 80% effective in preventing deaths, the government said in a report prepared…
Risk of rare blood clotting much higher in COVID-19 than for vaccines
Researchers at the University of Oxford have today reported that the risk of the rare blood clotting known as cerebral venous thrombosis (CVT) following COVID-19 infection is around 100 times greater than normal, several times higher than it is post-vaccination or following influenza. The study authors, led by Professor Paul…