April 3, 2026

Science Chronicle

A Science and Technology Blog

April 3, 2026

Science Chronicle

A Science and Technology Blog

Herd immunity

CoronavirusCOVID-19Herd immunityIndiaPublic HealthSARS-CoV-2
Prasad Ravindranath

Is the first coronavirus wave coming to an end in India?

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.

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CoronavirusCOVID-19Herd immunityICMRIndiaPublic HealthSARS-CoV-2Vaccines
Prasad Ravindranath

COVID-19: Challenges in achieving herd immunity through vaccination

But the government’s idea of vaccinating a “critical mass of people” for the purpose of breaking the virus transmission chain

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CoronavirusCOVID-19Herd immunityPublic HealthSARS-CoV-2
Prasad Ravindranath

T cell memory that cross-reacts with novel coronavirus does not prevent infection, researcher clarifies

  The presence of pre-existing T cell memory against four common cold coronaviruses which cross-reacts with novel coronavirus may not

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CoronavirusCOVID-19Herd immunityPublic HealthSARS-CoV-2Vaccines
Prasad Ravindranath

Is there a case for issuing immunity certificates to COVID-19 recovered people?

  While there is a clear case for ‘immunity passports’ with some restrictions for people who have recovered from COVID-19,

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Animal trialsClinical trialCoronavirusHealthHerd immunityPublic HealthSARS-CoV-2Vaccines
Prasad Ravindranath

Monkeys resist coronavirus reinfection; six DNA vaccines show promise in animal studies

Six rhesus macaque monkeys were resistant to reinfection following exposure to novel coronavirus. Compared with nose, the lungs had very

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CoronavirusHealthHerd immunityPublic HealthSARS-CoV-2World Health Organisation
Prasad Ravindranath

COVID-19: Aiming to achieve herd immunity naturally is ‘dangerous’, WHO warns

It was mistakenly assumed that as this disease spreads across the world, only the severe cases become apparent while most

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CoronavirusH1N1HealthHerd immunityPandemicPolioPublic HealthSARS-CoV-2VaccinesWorld Health Organisation
Prasad Ravindranath

Can we rely on natural herd immunity to end COVID-19 pandemic?

All previous influenza pandemics — 1918 Spanish flu, 1957 Asian flu, 1968 Hong Kong influenza, and 2009 H1N1 — came

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