Herd immunity

Did I catch Covid from a naked-rumped tomb bat?

Laikipia Until I promised to slaughter a fat-tailed sheep with a goat thrown in for a feast, the farm cowhands looked doubtful about going for their vaccinations. ‘Come on, it won’t hurt you,’ I cajoled. A panther-like man I’ve seen pursuing bandits with a rifle and reckless courage announced that he was frightened. The others nodded and rubbed their left arms. But at the offer of meat and sizzling fat over an open fire, everybody cheered up. Time was running short. A village clinic two hours away in Maasai country had phoned to say its supply of doses was sitting there unused and would I urgently muster some people? Vaccine

If we want herd immunity, we need mass testing

At the start of the pandemic, we talked a lot about herd (or community) immunity. But talking about the journey to herd immunity became toxic as it was variously linked to high infection rates, sacrificing the elderly, and the NHS becoming overwhelmed. The debate on herd immunity was restarted last week by Professor Karl Friston, of University College London, who told the Daily Telegraph that the 73.4 per cent vaccinated reached on Monday meant that ‘based upon contact rates at the beginning of the pandemic and estimated transmission risk, this is nearly at the herd immunity threshold.’ This is an outlying view: other academics questioned this analysis. Matt Hancock said

Has this Brazilian city reached herd immunity without lockdown?

Throughout the Covid crisis, the international response to the disease has rested on a simple assumption: that none of us have any resistance to it, being caused by a novel virus. Therefore, if allowed to let rip through the population, the virus would exponentially spread until around 60 – 70 per cent of us had been infected and herd immunity was reached. This was the assumption behind Neil Ferguson’s paper in March, claiming that Covid-19 would kill 500,000 Britons if nothing was done and 250,000 of us if the government carried on with the limited mitigation polices it was then following. Yet real world data has challenged this assumption. First

Herd immunity may only need 10-20 per cent of people to be infected

Since mid-March there has been an assumption that herd immunity against Covid-19 would not be achieved until around 60 per cent of the population has been infected. It is a figure which gave rise to the now-famous paper by Professor Neil Ferguson of Imperial College, which claimed that a herd immunity policy (which the government denies ever following) would result in the deaths of 250,000 people in Britain. That figure has been challenged by scientists who have questioned some of the assumptions behind it – for example, it assumed a mortality rate of 0.9 per cent which Imperial College itself has since revised downwards to 0.66 per cent, and some

The madness of #ToryGenocide

The hashtag #torygenocide was trending on Twitter all day Sunday. This is because seemingly rational people have got it into their heads that Boris Johnson is using the Covid-19 outbreak to orchestrate a social cull in the UK. There is a debate over the wisdom of the strategy the government has been advised to take by the chief scientific adviser. Robert Peston asks a question about testing that, if I’m honest, makes me wonder about the wisdom of how we’re going about this. Still, I am not a scientist. I don’t know whether Downing Street has taken the right or the wrong approach. I’m happy for others to have that

How ‘herd immunity’ can help fight coronavirus

This is an edited transcript of the interview with the chief scientific advisor Sir Patrick Vallance on the Today programme this morning.Justin Webb: We can talk now to Sir Patrick Vallance, who is the government’s chief scientific advisor and is on the line. Good morning to you. Sir Patrick Vallance: Good morning. JW: Could we start with sports events, which is what causes a lot of people to raise their eyebrows. And obviously we have the Cheltenham Festival, the big rugby match in Cardiff, 75,000 people tomorrow. What’s your thinking, at the moment, that they should go ahead? PV: Well, our reasoning is based on which interventions are going to have the