Public Health England found Pfizer’s COVID vaccine was 96 per cent effective and AstraZeneca’s vaccine 92 per cent effective in preventing hospitalization with the delta variant. A review of the study found that a dose of Pfizer’s vaccine showed 88 percent of efficacy against the symptoms caused by delta, compared with 93 percent for the alpha variant. When Delta spread to Israel, where over 62% of the population is vaccinated, the Ministry of Health determined that the efficacy of two doses of Pfizer and Biotech COVID vaccines fell to 39%, but the protection against serious diseases remained high.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, pointed to a handful of studies in a recent press release and said that doses of Pfizer and Biontech’s RNA vaccine were 80 percent effective in preventing infection with the delta variant, 88 percent for symptomatic disease, and 96 percent for hospitalization caused by delta. A study published in the New England Journal of Medicine used a negative case-control design test to assess the vaccine’s effectiveness against symptomatic diseases caused by delta variant versus alpha.
In addition, people who are not vaccinated are at a higher risk of infection, Wenseleer said. A recent analysis of groundbreaking cases among UCSF staff and employees in the rising deltas of the delta showed that unvaccinated people are five times more likely to become infected than vaccinated people and 2.5 times more likely to be hospitalized. A vaccine that is less than 90% effective at stopping the delta variant infection means that at least one in ten people will have a breakthrough infection.
While experts agree that vaccinations offer strong protection against infection with the delta variant, as well as serious illnesses and deaths, questions remain. It is unclear why delta causes more ground-breaking cases and infections in vaccinated people, as natural immunity to previous COVID-19 infections is generally rare. There is no known variant in which full vaccination works as well as delta to prevent serious diseases, but at least there are indications that this variant is a worrying development of coronavirus, and it seems likely that it will raise the stakes for countries that continue to have difficulty vaccinating their populations.
The communicable delta variant that led to a renewed rise in infections in countries such as the United Kingdom, the United States, Africa and Asia, is now found in over 130 countries according to the World Health Organization. It is the most transmitted variant of the coronavirus that has emerged outside China since late 2019 says Dr. Maria van Kerkhove, the epidemiologist and technical director of COVID-19 at the WHO. Delta, which became the dominant strain in the UK after 75 per cent of its total population was vaccinated, overtook the alpha strain, the most common strain, in some states earlier this month.
Last week, a so-called delta coronavirus variant that was identified in March in India caused over 90 per cent of new cases of COVID-19 in the UK, leading to 65 per cent increase in new infections since 1 May. Delta accounted for 70 percent of the nation’s variant cases at the beginning of July, according to the latest available data for sequencing the entire genome from the Canadian Public Health Agency. The COVID delta variant has not spared countries with high vaccination rates.
While vaccination rates in the United States and other countries are slowing down to get a vaccine, health experts are growing concerned that the delta coronavirus variant first identified in March in India could trigger a dramatic increase in cases and deaths in the US and around the world. The delta variant is responsible for more than 83% of all reported COVID-19 cases in the US and only 48% of the total US population is vaccinated, so the conditions are ripe for the further development and spread of SARS-CoV-2.
New research has shown that vaccinated people rarely develop COVID-19. When vaccinated people are infected with the delta variant, they can transmit much of the virus more easily than unvaccinated people. In Singapore, where delta is the most common variant, government officials reported that three-quarters of Coronavirus cases have occurred in vaccinated people, none of whom are well. Israeli health officials said that 60% of the current Covid-19 cases at the hospital involve vaccinated people.
This means that even if a vaccinated person with a delta infection does not show symptoms, he or she can transmit COVID-19 to others, including vulnerable populations. To further spread the delta variant in the US, the Centers for Disease Control and Prevention has recommended that vaccinated people begin wearing masks indoors and outdoors, especially in locations with high Covid-19 transmission rates. The CDC advised that all vaccinated people in high-transmission areas wear masks indoors last week, citing evidence that the delta variant causes a higher viral load in vaccinated people’s noses and throats.
Studies have shown that a two-dose vaccination is highly effective at preventing hospitalization and death and neutralization rates in vaccinated sera are significantly lower in the delta variant compared to the original strain. An effective vaccine is an effective sign that it can prevent the transmission of earlier coronavirus variants.
As evidence grows that the delta variant can infect vaccinated people faster than previous versions, concerns have been raised about its spread to Covid-19-10, according to leading COVID-19 experts. The lead epidemiologist for Covids 19, Dr. Maria van Kerkhove, clarified that Delta is not targeting children, as some reports suggest, but warned that the variant is circulating and could infect those who do not take appropriate precautions. She recalled that data indicate that vaccinated people can become infected and transmit the variant, although the likelihood is lower if a second dose is administered to achieve full efficacy.
We have shown in the UK that the delta variant can take hold over many months and that the Messenger RNA vaccine is effective against 80% of infections and 90% of serious diseases.
