A Variant Of Concern Has A Greater Impact Across All These Measures:
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Changes to receptor binding, often targeted by vaccines
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Significantly reduced antibody neutralisation
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Reduced vaccine or treatment effectiveness
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Diagnostic detection failures
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Evidence of increased transmissibility and more severe disease .
Out of tens of thousands of variants, only four are currently of concern to the WHO: Alpha, Beta, Gamma and Delta.
There is one step higher than a variant of concern called a variant of high consequence. Thankfully, we dont yet have one for SARS-CoV-2.
Pfizer 93% Effective Against Symptomatic Infection In Teens
In Israel, the Clalit Research Institute, in conjunction with Harvard University, conducted an observational study involving 130,464 COVID-19naïve adolescents aged 12 to 18 years, half of whom were vaccinated with the Pfizer COVID-19 vaccine from Jun 8 to Sep 14, 2021 matched participants were unvaccinated. During the study, 13,423 unvaccinated participants were vaccinated.
At the time of the study, Delta was responsible for more than 95% of new infections in Israel. The study is the largest peer-reviewed look at COVID-19 vaccine efficacy among adolescents in a nationwide setting and the first such study conducted at a time when Delta was the dominant circulating strain.
Over a median of 27 days after receipt of the first vaccine dose, Kaplan-Meier curves for infection showed a similar incidence of infection in the first few days after the vaccinated group received their first dose, after which the rise in incidence slowed among the vaccinated.
Estimated effectiveness of the Pfizer vaccine against infection was 59% 14 to 20 days after the first dose, climbing to 66% on days 21 to 27 and 90% 7 to 21 days after the second dose.
Efficacy against symptomatic COVID-19 was estimated at 57% 14 to 20 days after the first vaccine dose, rising to 82% on days 21 to 27 and to 93% 7 to 21 days after the second dose.
Moderna Vaccine Vs Omicron
There are not any studies that offer definitive estimates for the Moderna vaccines effectiveness against Omicron, though scientists believe it may be similar to Pfizer-BioNTechs vaccine.
A preliminary study of blood samples from 30 people who had received two doses of the Moderna vaccine showed that their antibodies were at least about 50 times less effective at neutralizing Omicron.
With a 50-microgram booster, however, antibodies increased 37-fold. On the other hand, a 100-microgram booster, the amount given to immunocompromised people as a third primary shot, increased antibody levels more than 80 times.
There is not yet enough data to give estimates for effectiveness. However, a booster has been shown to increase antibody levels significantly.
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Vaccines Effective Against Delta Variant
COVID-19 vaccines are effective at preventing hospitalizations and emergency department visits caused by the Delta variant, according to data from a national study. That data also indicate that Moderna’s vaccine is significantly more effective against Delta than Pfizer and Johnson & Johnson.
“These real-world data show that vaccines remain highly effective at reducing COVID-19 related hospitalizations and emergency department visits, even in the presence of the new COVID-19 variant,” said study author Shaun Grannis, M.D., M.S., Regenstrief Institute vice president for data and analytics and professor of medicine at Indiana University School of Medicine. “We strongly recommend vaccinations for all who are eligible to reduce serious illness and ease the burden on our healthcare system.”
The Centers for Disease Control and Prevention ‘s VISION Network analyzed more than 32,000 medical encounters from nine states during June, July and August 2021, when the Delta variant became the predominant strain. The results showed that unvaccinated individuals with COVID-19 are 5-7 times more likely to need emergency department care or hospitalization, similar to the overall effectiveness prior to the variant.
The study in Morbidity and Mortality Weekly Report is also the first analysis from the VISION Network to show a marked difference between the effectiveness of the mRNA vaccines . In the study’s time period:
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Unvaccinated People Are At Risk
In the U.S., there is a disproportionate number of unvaccinated people in Southern and Appalachian states including Alabama, Arkansas, Georgia, Mississippi, Missouri, and West Virginia, where vaccination rates are low, but cases are rising in other parts of the country as well. In September, health leaders in Idaho, which has one of the lowest vaccination rates in the country, expanded health care rationing throughout the state after the Delta surge led to a scarcity of resources for all hospitalized patients.
Children, teenagers, and young adults are a concern, too. A study from the United Kingdom showed that children and adults under 50 were 2.5 times more likely to become infected with Delta, says Dr. Yildirim. The U.S. has allowed Pfizer-BioNTech vaccinations for adolescents and teenagers since May, and, in early November, the CDC approved FDA authorization of the Pfizer vaccine for children ages 5-17.
As older age groups get vaccinated, those who are younger and unvaccinated will be at higher risk of getting COVID-19 with any variant, says Dr. Yildirim. But Delta seems to be impacting younger age groups more than previous variants.
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Very High Levels Of Protection Against Hospitalization
A recent analysis from PHE looks at how likely people who had an infection with the delta variant were to need treatment in the hospital.
The report puts the protection from requiring hospital treatment for COVID-19 at 71% after one dose and at 92% after two doses of the Oxford-AstraZeneca vaccine. The Pfizer vaccine was 94% effective at preventing hospitalization after the first dose and 96% after two doses.
In India, the Oxford-AstraZeneca COVID-19 vaccine bears the name Covishield.
The report, which has not been peer-reviewed yet, puts these percentages on a par with protection against the alpha variant, or B.1.1.7, which scientists first identified in the U.K.
These findings indicate very high levels of protection against hospitalization with the delta variant with one or two doses of either vaccine, the authors write.
It comes after an earlier report that indicates COVID-19 vaccines were less effective at protecting people from COVID-19 if they had only received the first dose of the Pfizer-BioNTech or Oxford-AstraZeneca vaccines.
However, in the analysis, which has not yet undergone peer review, the researchers measured any symptomatic case of COVID-19, regardless of severity.
Sputnik V And Coronavac
The makers of the Russian Sputnik V COVID-19 vaccine recently announced on Twitter that their vaccine was more effective against the delta variant than others. They added that they had submitted the data to an international peer-reviewed journal.
The company also said that it would soon be offering a booster shot specifically designed to work against the delta variant.
Until such time as the data are publicly available, it is not possible to assess the validity of these statements about the Sputnik V vaccine.
There is also little data available about how effective the Sinovac COVID-19 vaccine is against the delta variant. A recent Reuters news piece reports that over 350 doctors and medical staff in Indonesia developed COVID-19 despite receiving CoronaVac.
According to the report, Most of the workers were asymptomatic and self-isolating at home, said Badai Ismoyo, head of the health office in the district of Kudus in central Java, but dozens were in hospital with high fevers and falling oxygen saturation levels.
The region is seeing high numbers of infections, which experts believe are mostly due to the delta variant. Given the Reuters report, it is clear that more research is needed to establish exactly how well CoronaVac can protect from severe COVID-19 due to the delta variant.
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Omicron Vs Delta: Vaccines Seem Less Effective
Early estimates suggest that vaccine effectiveness against symptomatic infection with Omicron is significantly lower compared with the Delta variant.
A report by Imperial College London indicated that the risk of reinfection with Omicron was 5.4 times greater than the Delta variant. Previously having COVID-19 also afforded little protection against reinfection with Omicron.
This is such a contagious virus that it can spread not only among the unvaccinated, where I think it still has a very substantial risk of causing serious disease that might require hospitalization, but it can also spread among vaccinated persons, although the illness it produces among the vaccinated, particularly if youve had a boost, is generally mild and even without symptoms, said Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in Tennessee.
However, the Imperial College London study suggests that there is no evidence of Omicron having different severity from Delta, despite hospitalization remaining relatively low for the time being.
Omicron may not lead to more severe illness than Delta, a rapid and massive surge in infections could still overwhelm hospitals with sick patients. People who are unvaccinated remain at the highest risk, but also those who have not received a third dose of an mRNA vaccine, said Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York City.
What About Other Variants Of Concern Do The Vaccines Work Against Those Too
Some variants like the D614G attract a lot of media attention. But they dont necessarily affect vaccines, as my team was the first to demonstrate last year.
. There are also newer vaccines, such as the Indian Institute of Sciences warm vaccine Mynvax, which withstood all four variants of concern in our laboratory tests.
So we do have positive news. We dont yet have a SARS-CoV-2 variant of high consequence that significantly reduces the effectiveness of prevention or medical countermeasures.
Hopefully most people will be vaccinated before we face that situation. Getting a COVID-19 vaccine is one of the best protections we currently have.
But youll be safe knowing the vaccines available in Australia are effective at protecting against severe disease from the Delta variant.
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What Does This Mean To The Covid
Since there has been great confusion regarding the extent to which Covaxin can be effective against this new variant, this study has shed light on certain facts and helped put many vaccinated people at ease. It was earlier speculated that the Delta Plus variant, which contains a mutation of the K417N spike protein can probably escape the immune response generated by the vaccines. Virologists and doctors were anxious that this new variant could surpass the effect of antibody response, thereby rendering Covaxin ineffective. However, with this new study, vaccinations using Covaxin can continue throughout the country as it shows a modest level of efficacy against the Delta Plus variant as well.
What Are The Common Side Effects Of The Moderna Covid
The most commonly reported side effects were pain at the injection site, tiredness, headache, muscle pain, chills, joint pain, nausea and vomiting, swollen lymph nodes in the same arm of the injection and fever. Side effects typically started within two days of vaccination and resolved two or three days later.
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A Recent Study Found Covaxin Effective Against Delta Plus Variant
The Delta variant of COVID-19 was detected back in April 2021 in India. It was particularly dominant in Maharashtra, Kerala and Madhya Pradesh. As a result, government regulations have tightened the restrictions and in many parts of these states, lockdowns have been observed in the last 2 months.
There was widespread scepticism regarding the efficacy of the Covaxin and Covishield vaccines against this new variant. However, a recent study has revealed that Bharat Biotechs Covaxin is indeed quite effective against the new Delta Plus variant of the coronavirus.
Comparison With Other Studies
During the delta phase of the pandemic, breakthrough infections among fully vaccinated people have occurred, but the effectiveness of covid-19 vaccines against severe disease has remained robust. In our study, vaccine effectiveness against admission to hospital with the delta variant was high . Only five fully vaccinated people with the delta variant were admitted to hospital, no fully vaccinated people with non-delta variants were admitted, and no deaths in hospital occurred among any fully vaccinated people. This finding is consistent with previous studies suggesting that fully vaccinated people with breakthrough infections tend to have attenuated viral load, fewer symptoms, and shorter duration of illness, although severe outcomes can still occur.
Our real world findings complement existing immunogenicity and follow-up data from phase III trials of protection by mRNA-1273 against SARS-CoV-2 variants, including delta. High concentrations of neutralizing antibodies to delta and other variants were elicited following two doses of mRNA-1273. These antibodies were found to persist six months after vaccination, albeit at reduced concentrations compared with peak activity. Among phase III trial participants, incidence rates of covid-19 and severe covid-19 during the months when delta was predominant were lower among those who were vaccinated with mRNA-1273 more recently compared with those vaccinated initially .
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Do Variants Happen In Populations Where The Disease Is Spreading Fast
The more a virus is able to replicate and spread in a population, the greater the likelihood of mutations of consequence. Where the environment permits highly transmissible variants, we also expect disease severity to go up.
But if we halt transmission, we can suppress the spread of variants. This is why vaccinations and lockdowns are an essential part of a pandemic response. They drive transmission down, and drive the virus evolution towards less severe disease outcomes.
Natural Immunity Against Covid Lowered Risk More Than Vaccines Against Delta Variant New Study Says
Lisa Leutner/Associated PressEuronews and AFP
Unvaccinated people who had previously contracted COVID-19 and survived were better protected against the Delta variant than those who were only vaccinated, according to a new study published on Wednesday.
With the release of the research, which was published in its Morbidity and Mortality Weekly Report, the Centers for Disease Control and Prevention emphasised that “vaccination remains the safest strategy” against the disease.
“Viruses are constantly changing, including the virus that causes Covid-19,” the CDC said in a statement.
“The level of protection offered by vaccination and surviving a previous infection changed during the study period. Vaccination remains the safest strategy for protecting against COVID-19”.
The study also pointed out that relying on contracting the disease as a strategy to gain immunity potentially carries serious complications, such as hospitalisation, long-term health problems, and death, while vaccines have proven to be extremely safe and effective.
The study was conducted before booster doses were widely available, and before the emergence of the Omicron variant, which now accounts for more than 99 per cent of new cases in the US. It is, therefore, possible that the balance has shifted towards vaccination being more effective than immunity following infection.
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Breakthrough Infections Can Be Expected
Although were seeing more breakthrough cases in vaccinated people, and studies indicate that vaccine effectiveness against infection is over time, protection against severe disease or death remains strong.
Experts stress that vaccines are highly protective, even if theyre not 100-percent effective.
A preprint study that analyzed 161 vaccine breakthrough infections among 24,706 vaccinated healthcare workers found that although vaccinated people who contract the coronavirus have similar levels of the virus in their noses and throats as unvaccinated people, not all of it is as infectious.
The breakthrough cases presented with mild or asymptomatic infections, of which more than 90 percent were attributed to the Delta variant.
Additionally other experiments also showed that the viral shedding from vaccinated people was lower. Researchers hypothesized this was because some of the virus had already been neutralized by antibodies produced from the vaccine.
What About Transmission
A lingering question is to what extent the vaccines may be losing effectiveness at preventing onward transmission from people who become infected. After all, each of the new variants is characterised by increased transmissibility compared with the original SARS-CoV-2.
Akiko Iwasaki of Yale University says we wont know unless we can get more observational studies following household contacts.
One yet to be peer reviewed study looked at a single outdoor wedding near Houston, Texas, in April where all 92 guests were required to be fully vaccinated.7 A couple who had travelled from India later tested positive for delta, with one dying a month later. Of the people they interacted with at the wedding, four became ill with delta. One required monoclonal antibody treatment, but all four survived.
A recently released report from the US Centers for Disease Control and Prevention suggests that the viral load of vaccinated people infected with the delta variant is similar to that of unvaccinated people.8 People remain less likely to become infected in the first place when they have been vaccinated, however.9
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What Data Did We Use
We used healthcare data from around 99% of the Scottish population to answer questions about vaccine effectiveness.
This data is accessed through the EAVE II study platform. We looked at a group of over 1.5 million people aged 16 and over who had PCR tests between 1 April and 16 August 2021 in the community. From this group, nearly 115,000 people tested positive. We monitored the people who tested positive until 27 September 2021.
Community-based PCR tests can be used as a reliable test for whether someone has been infected with the Delta variant or not.
We defined COVID-19 deaths as anyone who died within 28 days of a positive PCR test, or with COVID-19 recorded as a cause of death on their death certificate.
Does The Covid
There is promising evidence to suggest that the current vaccines will protect you from most variants, or mutations, of COVID-19 that are currently spreading in the United States. It is possible that some variants might cause illness in some people after they are vaccinated. However, if a vaccine is found to be less effective, it could still offer some protection. Researchers are monitoring how the new COVID-19 variants may affect how vaccines will work in real-world scenarios. To learn more about vaccines and new variants, visit the Centers for Disease Control and Prevention.
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