Major news: We can't rely on "herd immunity".

[MelissaB]

Major news: The results of a cross-sectional immunity study in the Czech Republic rule out the possibility of relying on “herd immunity” in the event of a second wave of the coronavirus pandemic.

Link to tweet

Czech study shows extremely low level of collective immunity to COVID 19 virus

A government-commissioned collective immunity study aimed at establishing the level of Covid-19 infection within the population shows that the prevalence of the virus is in the order of “units per mille”. The result rules out the option of relying on “herd immunity” in the event of a second wave of the pandemic.

Tests on close to 27,000 people, based on detecting anti-bodies to COVID 19 in the blood, revealed only 107 positive cases. The rate of infection in different geographic locations ranged from zero to under five percent in the worst affected regions, which were quarantined a few weeks ago. In Prague, Brno and Litoměřice it was less than 0.6 percent.

The result is a far cry from early predictions that around 27 percent of the population may have been exposed to the virus without showing any symptoms and rules out the option of relying on “herd immunity” in the event of a second wave of the pandemic. Health Minister Adam Vojtěch said the country must prepare for such a scenario but, for now, the best option was to hold the set course.

“It makes sense to continue easing restrictions while protecting the most vulnerable groups of the population. Given this result we no longer need to fear an explosion of the epidemic nation-wide, what is important now is to focus on local outbreaks which still present a problem.”

... snip

“The result of the collective immunity study in this country is very similar to that in Austria. We pulled the brakes fast and prevented the spread of the virus in the population. This also provides an answer to the question whether the virus was not present in this country much earlier – like at the end of last year. We can’t say it wasn’t, but if it was it was clearly in isolated cases and there was no mass spread.”

More: https://www.radio.cz/en/section/curraffrs/czech-study-shows-extremely-low-level-of-collective-immunity-to-covid-19-virus

[Wellstone ruled]

1. Well,Sweden found out first hand

that was a false idea.

[Hortensis]

2. On top of everything, herd immunity can only be achieved AFTER

development and widespread use of a vaccine. The notion that this killer could be stopped simply by infecting enough people would be invalid even if recovered people did develop immunity. The numbers don't work even if it was more generally accepted that some of us had a duty to sacrifice our lives if necessary for the the economy.

"Fascism is the state. Liberalism is the individual." Benito Mussolini

[Igel]

3. That makes no sense.

Herd immunity was achieved before vaccines precisely by having enough people infected and recover to quench any transmission that starts.

Last estimate I saw said we'd need 60-70% with antibodies for that to happen, but the actual number depends on what R0 actually is.

The OP doesn't say people don't develop immunity. Just that so few have been infected that if there's a second wave in the near future there will not be herd immunity to fall back on as a defense.