Will there ever be such a thing as “immunity” to Covid-19?

I’ve had a couple people write to me believing that new Covid-19 deaths (or even cases) are declining in the US – perhaps because president Trump himself has said that at various times. What’s true is that the rate of increase in new deaths (i.e. the second derivative) has been gradually declining. The 7-day rate (which is required to smooth out a regular 7-day cycle in the total deaths numbers) was 22% two weeks ago, and yesterday it was 12%.

That’s an improvement, but it’s partially offset by the fact that the total number of deaths has increased by about 30% in the last two weeks – and this means the number of new deaths hasn’t declined all that much. We’ll never have the coronavirus defeated until total new cases are effectively zero and we have enough testing, quarantine isolation spaces (i.e. hotel rooms) and contact tracing available that we can jump on any new hot spot and keep it from spreading any further. We’re still a long way from that point. Even if the virus is spreading less rapidly in the summer, it will inevitably jump back in the fall, possibly at a higher level – as happened in the 1918 Spanish flu pandemic.

Remember: on March 2 there were 100 reported cases in the US. Less than three months later, there are over 1.5 million reported cases, and that’s without doubt some fraction of actual cases. Even if we got total cases down to just one or two hundred on September 1, we would still have well over a million cases (and deaths comparable to today’s levels) by November. There’s no such thing as a “truce” with the coronavirus. Only complete victory will ultimately save us.

And what will constitute “victory”? Of course, the White House is keying on the idea that a vaccine will quickly be discovered and quickly become widely available - because we will have prepared the manufacturing and distribution infrastructure beforehand. This is kinda sorta what the US is trying to do now, but two cold facts remain: 1) There may never be a vaccine, just as there isn’t a vaccine for AIDS, 40 years after that epidemic started; and 2) The presence of antibodies in your blood (which is of course the whole goal of a vaccine) may not actually confer real immunity to the novel coronavirus.

Kevin Perry pointed out to me yesterday that 13 sailors from the USS Roosevelt, who had Covid-19 but subsequently had two negative tests, have now tested positive again. There are two possible explanations for this. The less scary one is that the virus has a way of hiding in the body, so this may mean the negative tests just didn’t look in the right places (although even this is a scary thought, since it means that a lot of the people who think they’ve recovered and believe they have “immunity”, really don’t. They’ll end up infecting family members and others because they think social distancing is no longer required for them). Yet it would be very hard, if not impossible, to design a test to find the virus wherever it happens to be hiding.

But the really scary explanation – and it took a while for this to sink in after Kevin raised it in his email – is that even having been infected might not confer immunity to the virus. And if that’s the case, then any vaccine will most likely not confer immunity either (of course, antibodies will be produced both in recovery and in the case of vaccination. But it might not be a high enough level to confer immunity).

Of course, these are really scary thoughts. Do you think the White House is considering them now, and making contingency plans in case its vaccine hope proves wrong? Didn’t think so.

The numbers

These numbers are updated every day, based on reported US Covid-19 deaths the day before (taken from the Worldometers.info site, where I’ve been getting my numbers all along). No other variables go into these numbers – they are all projections based on yesterday’s 7-day rate of increase in total Covid-19 deaths, which was 12%.

Note that the “accuracy” of the projected numbers diminishes greatly after 3-4 weeks. This is because, up until 3-4 weeks, deaths could in theory be predicted very accurately, if one knew the real number of cases. In other words, the people who are going to die in the next 3-4 weeks of Covid-19 are already sick with the disease, even though they may not know it yet. But this means that the trend in deaths should be some indicator of the level of infection 3-4 weeks previous.

However, once we get beyond 3-4 weeks, deaths become more and more dependent on policies and practices that are put in place – or removed, as is more the case nowadays - after today (as well as other factors like the widespread availability of an effective treatment, if not a real “cure”). Yet I still think there’s value in just trending out the current rate of increase in deaths, since it gives some indication of what will happen in the near term if there are no intervening changes.

However, it’s 100% certain that deaths won’t stop at the end of June! They might decline some more this summer, but Drs. Redfield (CDC head) and Fauci both predict there will be a new wave of the virus in the fall, and one noted study said there was a good probability the fall wave would be greater than the one we’re in now, as happened in the 1918 pandemic.

Week ending	Deaths reported during week/month	Avg. deaths per day during week/month	Deaths as percentage of previous month’s
March 7	18	3
March 14	38	5
March 21	244	35
March 28	1,928	275
Month of March	4,058	131
April 4	6,225	889
April 11	12,126	1,732
April 18	18,434	2,633
April 25	15,251	2,179
Month of April	59,812	1,994 (= 1 death every 44 seconds)	1,474%
May 2	13,183	1,883
May 9	12,592	1,799
May 16	10,073	1,439
May 23	10,945	1,564
May 30	12,275	1,754
Month of May	50,553	1,631 (= 1 death every 53 seconds)	85%
June 6	13,766	1,967
June 13	15,438	2,205
June 20	17,313	2,473
June 27	19,416	2,774
Month of June	71,695	2,390 (= 1 death every 36 seconds)	142%
Total March - June	186,117

Red = projected numbers

I. Total deaths

Total US deaths as of yesterday: 93,558

Increase in deaths since previous day: 1,573 (vs. 1,005 yesterday)

Percent increase in deaths since previous day: 2% (vs. 1% yesterday)

Yesterday’s 7-day rate of increase in total deaths: 12% (This number is used to project deaths in the table above. There is a 7-day cycle in deaths, caused by lack of reporting over the weekends from closed state offices. So this is the only reliable indicator of a trend in deaths, not the one-day percent increase).

II. Total reported cases

I no longer pay any attention to the reported case number. It is a huge underestimate of actual cases, which is at least 5-10 times what’s reported. This is because of the huge shortage of testing capacity. For reported cases to be anywhere near actual cases, we would need to be doing millions of tests a day. I believe the US has done fewer than 7 million tests since the start of the pandemic.

Total US reported cases: 1,571,131

Increase in reported cases since previous day: 20,592

Percent increase in reported cases since yesterday: 1%

Percent increase in reported cases since 7 days previous: 12%

III. Deaths as a percentage of closed cases so far in the US:

Total Recoveries in US as of yesterday: 361,227

Total Deaths as of yesterday: 93,558

Deaths so far as percentage of closed cases (=deaths + recoveries): 21% (vs. 21% yesterday) Let’s be clear. This means that, of all the coronavirus cases that have been closed so far in the US, 21% of them have resulted in death. Compare this with the comparable number from South Korea, which is below 3%. China’s is 6%. The reason this number is so high is that total reported recoveries are so low. I’ve been assuming since March 26, when the recoveries number was first published, that it would rise, so that this percentage (which was 41% on March 26), would be far lower than it is now. But it still has to drop a long way, in order for the US to have anything less than millions of death over the course of the pandemic – since we seem to have given up on controlling total cases in any meaningful way.

I would love to hear any comments or questions you have on this post. Drop me an email at tom@tomalrich.com