Some experts are questioning whether a "booster" dose will even be necessary for most healthy people in the coming months as epidemiologists continue to keep a close eye on the spread of the "Delta" mutant COVID strain that is partly responsible for the UK's decision to delay the unwinding of its lockdown. In wealthy countries like the US, the link between infections and deaths has diminished. Now, in some places, instead, the focus is shifting to learning to live with COVID, like we have learned to live with the flu.
In this paradigm, the number of confirmed cases won't matter as much as the number of hospitalizations.
"It’s possible we’ll get to a stage of only monitoring hospitalizations," said Jennifer Nuzzo, an epidemiologist at Johns Hopkins Coronavirus Resource Center, which has built one of the most comprehensive platforms to track the virus and its impact, making it a critical source of international data on the pandemic.
Before vaccinations took off in the US, UK and Europe, a spike in case numbers almost invariably led to a surge in hospitalizations and deaths, perhaps with a modest delay. But now, with most of the most vulnerable already vaccinated, scientists and government officials are keen to see whether the widening scope of vaccinations will finally break the cycle. The situation in the UK is the most compelling example to date.
Roughly 46% of the British population is fully vaccinated, helping reduce daily deaths to the lowest level since last summer. Yet cases of the delta variant, a more transmissible strain first identified in India, have almost doubled in the past week, Public Health England said Friday. Hospitalizations also ticked higher, though most of the hospitalized patients haven’t been fully vaccinated.
But even if the virus spreads further among children and non-vaccinated young adults, the true test of the immunization campaign will be whether hospitalizations and deaths stay low. If they do stay low, many experts will take this as a sign that COVID has transformed into a pandemic into a manageable seasonal illness.
Once this happens, scientists say comparing the prevalence of COVID to the flu, which kills about 650K people globally each year, will become an important yardstick come next fall and winter. COVID has killed more than 3.8MM people since the start of 2020, but vaccinated countries should eventually be able to treat its periodic resurgences in the same way as they do the flu.
“Comparing to seasonal influenza impact is an appropriate one when talking about things like closing schools,” said Nuzzo. “What do we do with influenza? Would we do this in a normal flu season?”
Already, several US states have reduced the frequency with which they are reporting new COVID-19 cases. Other countries are worried about taking their eye off the ball, even for a minute. For an example of just how dangerous this can be, critics point to Taiwan, which saw cases briefly spike higher earlier in the spring.
"When we look at Taiwan, which is the best of the best, it underscores the vulnerability of these countries,” said Nuzzo. “They are not going to be able to relax until they’re able to vaccinate more widely.”
As we have previously reported, the FDA has been laying the groundwork for this shift since shortly before Biden was inaugurated. Evidence has existed for months suggesting that the "casedemic" - epitomized by the surge in cases seen during the holiday season through January - was the result of overly sensitive testing picking up too many asymptomatic "cases."
How? Well, as we have reported, "cycle thresholds" (Ct) are the level at which widely used polymerase chain reaction (PCR) test can detect a sample of the COVID-19 virus. The higher the number of cycles, the lower the amount of viral load in the sample; the lower the cycles, the more prevalent the virus was in the original sample.
Looking ahead, scientists have warned that even as vaccination numbers improve, there's always a risk that the virus could evolve into a more vaccine-resistant strain.
As things stand, don't expect the US, or any country, to reach the zero-case threshold any time soon. At this point, officials expect that COVID will be something "we have to live with....there will be new variants," said Marc Baguelin, an epidemiologist at Imperial College London. "It's something that's always happening in the background."