The Telegraph reported on Monday that more than half of patients counted in the COVID hospitalisation numbers did not test positive until they were admitted. (Everyone must take a COVID test before entering a hospital in England.) Only 44% tested positive prior to being admitted.
The data seen by The Telegraph correspond to 22nd July. On that date, 827 “COVID-19 patients” were admitted to hospital, according to the Government’s coronavirus dashboard. However, the true number of people hospitalised because of COVID-19 may be far lower.
Crucially, the hospitalisations numbers do not exclude people who were admitted for non-COVID reasons (say, a broken leg) but simply happened to test positive upon admission.
Given that tests are now widely available, it seems likely that someone who had symptoms resembling those of COVID-19 would take one before going to hospital. Consequently, many of those who only test positive upon arrival may be suffering from other ailments. The true number of “COVID-19 patients” admitted to hospital last Thursday could be as low as 363 (i.e., 44% of 827).
The Telegraph story highlights an important point, which lockdown sceptics have made over and over again during the pandemic. Testing positive on a PCR or lateral flow test is not the same thing as having the disease COVID-19. (It would be more accurate to describe a positive test result as “an instance of SARS-Cov-2”.)
One important implication is that the number of hospitalisations and deaths – indicators that supposedly capture the impact of the pandemic on public health – can increase simply due to higher transmission.
According to the ONS’s Coronavirus Infection Survey, the percentage of people in England infected with the virus went from 0.22% in the week ending 19th June to 1.36% in the week ending 17th July – an increase of 1.1 percentage points.
In July of 2019, there were 1.3 million inpatients admissions, or 42,000 per day. If the percentage of inpatients testing positive rose by 1.1 percentage points due to a general increase in transmission, that would yield an additional 462 “COVID-19 patients” by the end of the month.
Now this calculation isn’t an exact representation of what’s going on at the moment. We know that infections are concentrated among people in their 20s and 30s, who are unlikely to be hospitalised for any reason. But it illustrates the point that even the hospitalisation numbers have to be taken with a grain of salt.