As the virus evolved, our perception of protection conferred by vaccines changed dramatically. From the popular notions of herd immunity and vaccinating our way out of the pandemic, the discussion is now centred around booster doses and the eventuality of living with the virus. As the virus evolved, our perception of protection conferred by vaccines … Continue reading How the idea of vaccine protection changed in one year
The emergence of highly contagious new variants, breakthrough infections even among the fully vaccinated and such people spreading the virus to others, and reinfections in the unvaccinated have made the race to reach the magical herd immunity threshold to successfully break the transmission chain and return to normal times looks like chasing a mirage. In … Continue reading Is the race to reach herd immunity like chasing a mirage?
While 67.6% of the Indian population appears to have antibodies either from natural infection or vaccination, as per the fourth sero survey , Dr. Srinath Reddy dispels the wrong notion that India is close to reaching herd immunity and explains the uncertainty of protection even among those already infected. The fourth sero survey conducted across … Continue reading Erroneous to conclude that we have attained herd immunity, says Srinath Reddy
Even as daily new cases and test positivity rates have been declining in Kerala since end-January, the Health Ministry has been mischievously implicating the State for a surge in new cases. While researchers think the decline could be due to infection rate reaching close to herd immunity, serosurvey results show otherwise. Kerala pioneers post-COVID care … Continue reading As cases spike in a few States, what is causing a decline in Kerala?
The number of daily fresh coronavirus cases has been steadily dropping from a peak of nearly 98,000 cases on September 16 to below 25,000 daily cases in the last few days with no spike seen nationally. The cases have been reducing despite the festival season, winter, large gatherings and not so good adherence to non-pharmaceutical interventions. However, the cumulative test positivity rate nationally is 6.1% as on December 23, which suggests we aren’t near the end of the first wave immediately.
Where everyone is equally affected by COVID-19 disease, immunisation should be available to all when vaccines are ready. It is important to remember that vaccines are a tool to promote health equity. If the goal is to achieve herd immunity, we will need about 70% of the population to be covered. Breaking the chain of … Continue reading COVID-19: Challenges in achieving herd immunity through vaccination
The presence of pre-existing T cell memory against four common cold coronaviruses which cross-reacts with novel coronavirus may not prevent SARS-CoV-2 infection, but at most be able to reduce the severity of COVID-19 disease and probably prevent people from dying. The T-cell memory does not allow populations to reach herd immunity when just 10-20% are … Continue reading T cell memory that cross-reacts with novel coronavirus does not prevent infection, researcher clarifies
While there is a clear case for ‘immunity passports’ with some restrictions for people who have recovered from COVID-19, the issue of handing out such certificates is an ethical minefield. It has a dangerous public health risk too as it will encourage people to indulge in risky behaviour in order to get infected. As on … Continue reading Is there a case for issuing immunity certificates to COVID-19 recovered people?
Six rhesus macaque monkeys were resistant to reinfection following exposure to novel coronavirus. Compared with nose, the lungs had very less virus when challenged. In another study, the researchers tested six prototype DNA vaccines that showed good protection in rhesus macaques.Evidence from studies carried out on rhesus macaque monkeys suggest that once infected with novel … Continue reading Monkeys resist coronavirus reinfection; six DNA vaccines show promise in animal studies
It was mistakenly assumed that as this disease spreads across the world, only the severe cases become apparent while most people would indeed be infected as reflected in sero epidemiology results. But preliminary results from sero epidemiology studies are showing the opposite. The World Health Organisation has condemned the “dangerous” concept of herd immunity for managing the coronavirus pandemic. Dr. Michael Ryan, … Continue reading COVID-19: Aiming to achieve herd immunity naturally is ‘dangerous’, WHO warns