Great News on the Covid front in Costa Rica

There has been a string of great news on the Covid front in Costa Rica, and since that’s quite rare and notably under-reported, I offer the right now Eric report:

Today in Perez Zeledon, we had our first zero reported cases day

Across Costa Rica, this ‘epidemiological week’ showed the lowest cases since the pandemic began, and similarly, hospital beds and ICU use are at their lowest points as well.

Many months ago Costa Rica’s health minister estimated we could reach something like herd immunity between October and December of this year, and he seems to have been correct. (The virus technically is likely endemic, so true ‘herd immunity’ would not be possible, but a form of functional herd immunity where numbers of deaths are ‘more natural ’seems to have arrived).

Of course the future is unknown since other variants could be more resistant to vaccines and/or natural immunity, but even there we’ve got some great news, since our new friend the Omicron variant appears to be more transmissible (bad) but bringing lower mortality and morbidity (very good), which actually means that as this variant out-competes Delta, we can cautiously expect to see much less sickness and death as this newest ‘wave’ spreads across the planet.

We may see cases go up (especially as some regions ramp up testing to assess seroprevalence of the new variant), but cases don’t matter, rather hospitalizations and deaths do, so despite however the media and ‘public health’ might try to spin it, a more-transmissible-but-less-deadly variant is likely very very good news.

This morning a friend posted about the zero cases in Perez Zeledon, to which I responded: “That’s amazing! About two years into this, it appears that in Costa Rica most people have taken two vaccines (70% ish), and also seems that most of the country (70-80% ish) has recovered from prior infection. The combination of those two (overlapping) quantities likely put us well above the cumulative protection figures that were sought for achieving herd immunity”

Since media and ‘public health’ rarely discuss natural immunity, it would be understandable if many people reading this didn’t follow my assumptions or agree with my estimates, so it could be useful to expand on what I observe and from where I’m getting my info. (And happy to clarify anything if I can.)

I think the number of double vaccinated in Costa Rica is somewhat well established, though different sources put it a little higher or lower and some include children or not, but overall appears about 65-75% double vaccinated depending on methodology.

For the second figure on natural immunity, the figures are not nearly as well tracked, and are confounded somewhat since it is understood that ‘known recovered’ is a much smaller quantity than ‘actual recovered’, but isn’t known by what factor. Some recent health ministry data put ‘known recovered’ at ~ 550,000 people, which is 13% of the population greater than 12 years old.

This study in Nature (https://www.nature.com/articles/s41598-021-82662-x) showed that in one region/study there were 7x as many people estimated to be recuperated as had been confirmed as cases. (Which is logically coherent since the majority of people who encounter SARS-CoV-2 are asymptomatic or nonsymptomatic, and thus don’t present to the health system for inclusion in the figures).

Multiplying 13% x 7 would give 91%, however this group overlaps with the vaccinated group, so the actual figure is lower by an unknown margin.

Coming from the other side, in March a McKinsey & Co study of Latin America showed “30%+” having natural immunity (https://www.mckinsey.com/industries/healthcare-systems-and-services/our-insights/when-will-the-covid-19-pandemic-end, scroll past first entry to chart in middle of second entry). However that figure was 8+ months ago, and since then we’ve had the much more transmissible Delta variant, which spreads through populations much quicker. Again the exact rate of growth is estimated rather than known, but in general when reviewing exponential growth curves, if the figure was ~30% some time ago and was growing ever more rapidly exponential, by 8 months later it is consistent to presume the figure as massively higher, likely 80-90%+.

So acknowledging the limitations in our data, but noting that multiple forms of analysis point to the same ultimate conclusion, it seems that natural immunity in Costa Rica as of December 2021 is likely to be conservatively at 70-80%, and possibly notably higher.

The health minister of Costa Rica also said in July (https://qcostarica.com/costa-rica-expected-to-achieve-herd-immunity-by-october-and-december) that he expected that between October to December of 2021 Costa Rica would reach some version of herd immunity via a combination of those with vaccine-derived protection plus those with previous-infection-derived immunity.

All of this is consistent with what virologists and epidemiologists were saying they expected to happen about two years into a pandemic, that most of the planet would have encountered the virus by this point, and the combination of vaccine protection and natural immune system protection would lead to observed hospitalizations and deaths falling to their lowest point (not zero which isn’t likely possible, but a very low point which would exit the previous definition of pandemic).

Moving forward I would love to see individuals and communities put a lot more effort on general good health, improving immune function, addressing underlying conditions, maintaining good hygiene, and improving any aspect of health that feels realistic (sleep, diet, exercise, etc), in order to stay healthy against future threats. People who like the protection type/amount from vaccines could continue being readily supplied them, but also would be great if we see a return to more broad definitions of health which factor in all relevant sources and threats instead of just one.