Coronavirus Briefing Newsletter – Times of India

Box

The Count
  • India’s health ministry Thursday confirmed 36,401 new cases and 530 fatalities, raising the total to 32,322,258 cases (364,129 active cases) and 433,049 fatalities.
  • Worldwide: Over 209.2 million cases and 4.39 million fatalities.
  • Vaccination in India: 565,630,291 doses. Worldwide: Over 4.8 billion doses.
TODAY’S TAKE
Studies show vaccine efficacy declining against Delta variant
Studies show vaccine efficacy declining against Delta variant
Two studies — one by the Indian Council of Medical Research (ICMR) and the other by Oxford University — show that the efficacy of vaccines against the delta variant of SARS-CoV-2 is declining.

What the ICMR study found

  • Authorised by the Institutional Ethics Committee of ICMR-National Institute of Epidemiology, Chennai and published in the Journal of Infection this week, the study found that the delta variant had the potential to infect both vaccinated and unvaccinated people.
  • The silver lining was that the “proportion of patients progressing to severe illness and mortality was lower in the vaccinated group which is the case globally.” The study says that while “no deaths were reported in the fully vaccinated group…three partially vaccinated (patients) and seven unvaccinated patients died.”
  • The study was conducted in Chennai which was among the worst affected cities during the second wave of Covid-19 with daily fresh infections hovering around the 6,000 mark during the first three weeks of May — this, despite a relatively high seroprevalence of 45% as of October-November last year.

What the Oxford study found

  • A study by Oxford University, which analysed more than 3 million nose and throat swabs collected from across the UK, found that the efficacy of vaccines — against the delta variant — by Pfizer-BioNTech and AstraZeneca declined from 85% and 68% respectively, two weeks after the second dose, to 75% and 61% respectively, 90 days after the second shot.
  • The study is pertinent since Oxford University partnered with AstraZeneca to develop the latter’s Covid-19 vaccine, which is administered in India under the Covishield brand name. The study found that the decline in vaccines’ efficacy was more pronounced in those aged 35 years and above than those below 35.
  • Researchers who led the study also say that the efficacy of both vaccines would likely be the same after 4 to 5 months of the second dose — though they couldn’t say to what level the efficacy would be reduced by that time.
  • The study also found that fully vaccinated people who get infected with the delta variant had similar levels of virus in their bodies as those who were unvaccinated. This cast doubt on the possibility of achieving herd immunity.
  • Sarah Walker, a professor of medical statistics and epidemiology at Oxford, said the hope was vaccinating lots of people could protect the unvaccinated, but the fact that the vaccinated can have high levels of virus and thereby possibly transmit the virus, suggests that “people who aren’t yet vaccinated may not be as protected from the Delta variant as we hoped.”
  • Experts say that the declining efficacy could be because of waning immunity, which would also support the argument for a third shot. Past studies have shown that antibody levels decline over time but we still don’t know at what level they stop being protective.
TELL ME ONE THING
Week 2 is the most crucial in Covid fight: Study
Week 2 is the most crucial in Covid fight: Study
  • A person suffering from Covid-19 needs hospitalisation if the infection progresses to the inflammatory phase. This usually happens in the second week of illness. Medical intervention in this period can prevent a third of the deaths caused by the coronavirus.
  • Doctors at the All India Institute of Medical Sciences (AIIMS) came to this conclusion after analysing the factors responsible for critical illness in Covid patients who were admitted in the institute’s Jhajjar centre between April and June. The centre, designated a Covid facility, admitted 2,080 Covid patients in the three months, of whom 406 (20%) died.
  • Covid progresses in three phases: early infection, pulmonary phase and hyper-inflammation phase. While the early phase appears to be due to the virus itself (5–7 days), the two later phases are thought to be due to the inflammatory response (7–15 days from disease onset).
  • Dr Sushma Bhatnagar, chairperson of Covid services, AIIMS, who is also the corresponding author of the study, told TOI that hospital admission in the third or fourth week of illness increased the odds of Covid death. Other risk factors included pre-existing comorbidities and old age.
  • She added: “Vaccination and hospitalisation in the second week of illness reduced the odds of death, respectively, by 30% and 36%.”
  • Early admission to the hospital, especially during the inflammatory phase could make a difference by reducing mortality, doctors say. More details here
Follow news that matters to you in real-time.
Join 3 crore news enthusiasts.

Written by: Rakesh Rai, Judhajit Basu, Sumil Sudhakaran, Tejeesh N.S. Behl
Research: Rajesh Sharma

Source link

Leave a Comment