Ensuring Delta remains under control
CLINICAL MATTERS
With few exceptions, the biggest one being China, most of the world has pretty much moved on from a COVID-19 elimination strategy. Zero COVID-19, which was the goal early in the pandemic, became a near-impossibility with the rise of the Delta variant. With its extreme infectiousness even with fleeting contact, the strategies previously used to control the earlier incarnations of SARS-CoV-2 were found to be woefully inadequate against Delta.
The old definition of close contact being 15 minutes of contact within one meter of an infected patient became obsolete when it was shown that people could get infected Delta within just one to two minutes. Contact tracing became nearly impossible with the faster time to infectiousness of Delta, sometimes in as little 30 hours from exposure. Generations of transmission began to overlap and contact tracers could no longer tell where the infections were coming from. With an increase in breakthrough infections due to this variant, the CDC was forced to take back its declaration that vaccinated individuals no longer needed to wear masks indoors. In fact, the CDC started to recommend the wearing of double masks to slow down the spread of Delta.
In the Philippines, after the Alpha/Beta spike started to recede in April 2021, the continued use of extra layers like face shields over face masks along with strict facility-based quarantine protocols delayed the entry of Delta into the community. As Delta, however, became the predominant variant globally, it eventually made its way into the community and started to wreak havoc. In anticipation of a surge in cases, the IATF preemptively declared a lockdown in early August 2021, with the MMDA and the Metro Manila mayors embarking on an enhanced vaccination program.
Peaking at 26,000 cases in one day, the case numbers put a severe strain on the healthcare system. Thanks to the early lockdown and less severe cases from widening vaccination coverage, however, the healthcare system buckled but did not break. The current case numbers of 1,000 to 2,000 a day reflect the value of the pre-emptive strategy.
In a reflection of more targeted containment strategies, the impact on the economy of the early lockdowns was much less than that of the 2020 lockdowns. The fact that the economy grew by 7.1 percent in the third quarter despite the lockdowns shows that many businesses and consumers are adapting to the pandemic. This growth was much higher than expected for this quarter. It reflected the controlled and precise implementation of the August 2021 ECQ in Metro Manila. Despite extreme pressure on the IATF to lock down immediately given panic-inducing projections from some groups, proper scientific modeling by FASSSTER showed that a short delay in the lockdown would have the same effect on case numbers as a sudden hard lockdown. This gave businesses some time to adjust their logistics and manpower schedules and limited losses from a spoilage and unanticipated delays. The superhuman effort of MMDA and the Metro Manila mayors in enhancing both vaccination and PDITR strategies resulted in a better-than-projected drop in active cases. Case rates continue to drop and resulted in de-escalation of the alert levels.
Whether these numbers are sustainable is another matter. The problem with a containment strategy that works very well is that the enticingly low numbers precipitate calls for dismantling restrictions as fast as possible. The plan as formulated was to open gradually and safely. This is because current case numbers will not be reflective of real-time transmission. Instead, present case numbers show infections that were transmitted at least two weeks ago due to the incubation period of COVID-19 and expected timelines of infection. The intent was to start opening with high-yield and essential services, and gradually relax curbs as more data come in over time. From Alert Level 4 where only essential services were allowed, more and more non-essential activities were added, along with expansion of venue capacity, especially for fully vaccinated individuals. These proposals were cautiously and carefully vetted by the Department of Health and its resident experts. The clamor for even more capacity and relaxation of restrictions from a pandemic-weary population was considerable. In particular, the highly politicized call to abolish the use of face shields on top of masks while accelerating mobility removes a safeguard that can serve as circuit breaker. Higher mobility for all ages with fewer safeguards can cause an exponential rise in cases, which can precipitate another lockdown cycle.
A highly vaccinated populace is not enough to prevent subsequent spikes in cases, as the recent experience of Singapore and Denmark has shown.
The high vaccination rates, however, have significantly contributed to reducing deaths and severe disease. Given the extreme transmissibility of Delta and the decrease in clinical efficacy of the vaccines against it, vaccination needs to go hand in hand with public health measures that decrease the risk of transmission as well as contingency measures that can interrupt nascent outbreaks. A granular lockdown approach as adopted with the alert level system utilizes a risk-based approach with specific metrics designed to arrest the spread of COVID-19 before it gets out of hand.
While vaccination is essential to ending the pandemic, relying on vaccination alone to defeat the pandemic will result in failure of containment. Many countries are rolling out boosters to see if this helps keep case numbers low. There is no guarantee this will be successful but even if this works, the threat of new variants remains. For countries with low vaccination rates with limited vaccine supplies, prioritizing vaccination of the unvaccinated will prevent more cases and deaths than rolling out boosters to those who already completed their primary series. Boosters can be started once a majority of the populace has been protected.
The arrival of effective outpatient treatment for COVID-19 will have a significant impact on our future strategies. Molnupiravir decreases the risk of death from COVID-19 in high-risk populations. It will complement, but not replace vaccination. Vaccination still prevents a certain proportion of infections, and breakthrough infections tend to be mild and less contagious. For unvaccinated individuals who end up being treated with molnupiravir, the risk of severe disease and death can be lowered but is still significant. In addition, long COVID-19 syndrome can be crippling, along with unknown long-term consequences of SARS-CoV-2 infection. Another drug, Paxlovid, is showing even higher efficacy in preliminary reports. Approval is still pending, and more information is forthcoming. These two drugs and forthcoming ones can decrease the pressure on healthcare systems when a spike in cases occurs by limiting the number of people who develop severe disease.
In summary, case numbers in the Philippines have tremendously improved and the Delta wave has receded. The threat of subsequent spikes remains, however, especially if safeguards are relaxed too fast. Vaccination needs to go hand in hand with public health standards in order to keep cases low and manageable. New effective drugs will serve as insurance policies to protect our healthcare system and will increase confidence in further opening society. Cautious optimism will consolidate gains and ensure a good Christmas and a better New Year.