1. What does endemic mean?
An epidemic is a wave of disease in one location; it becomes a pandemic when it spreads worldwide. When the number of new cases slows and then declines, usually at a lower level, the disease is considered endemic. There may still be spikes in cases. And endemic diseases can take a heavy toll; the flip side of SARS-CoV-2 being accepted everywhere is that nowhere is safe. What’s gone is the element of surprise. Instead, a balance is established: society knows it has to live with the pathogen, grapple with a baseline of disease, and prepare for future flare-ups. Ideally, infections would no longer overwhelm healthcare, mortality rates would decrease, and disruptions to daily life, such as schools and businesses closing, would decrease.
2. How does this happen?
Confirmed cases of SARS-CoV-2 infection remained significantly high as 2022 drew to a close. There were nearly 2 million worldwide in the first week of November, which was an underestimation as many cases are now validated with home testing and never reported to authorities. Yet two developments led most parts of the world to view Covid as endemic: the spread of the less severe omicron variant of SARS-CoV-2 and a build-up of immunity that further reduced the likelihood of people becoming seriously ill from infections. . The built-up immunity is the result of people being vaccinated and/or infected with SARS-CoV-2 and surviving. By mid-November, the number of daily confirmed deaths from Covid per million people worldwide had fallen to 0.18, from a peak ten times higher in January 2021. This still meant many people – some 1,400 – were dying daily before winter dawned. in the northern hemisphere, which carries the risk of a seasonal surge typical of respiratory viruses. If the rate settled there, Covid would rank between malaria and Parkinson’s disease as the 17th deadliest disease worldwide, based on 2019 data for other conditions.
3. What are the precedents for viruses becoming endemic?
The most commonly cited example of a respiratory virus that became endemic is the virus that caused the 1918 flu pandemic; elements of that flu strain, called A/H1N1, are still circulating to this day. The flu strains that caused outbreaks in 1957, 1968 and 2009 (swine flu) are all eligible. Four other coronaviruses are endemic. They manifest as the common cold and are believed to be responsible for a large proportion of respiratory infections in adults and children. The original SARS coronavirus, first discovered in Asia in 2003, never became endemic because it was effectively eradicated using aggressive public health measures.
4. What is China’s approach?
Rather than accepting Covid as endemic, China is pursuing a policy of fighting any outbreak with a barrage of targeted testing, contact tracing and quarantines, with city-wide lockdowns as the last resort. This has resulted in the lowest number of confirmed Covid deaths per capita in the world, except in Burundi and North Korea. In November, China eased some of its rules, but only modestly. Although tackling them has a high economic cost, dumping them poses huge challenges. China has limited Covid vaccinations to homegrown inoculations that are not as potent as the mRNA versions that are the backbone of global immunization efforts. When vaccines first became available in China, the country’s elderly largely shunned them out of fear that they were being developed too quickly. By the time the injections were proven safe elsewhere, vaccine reluctance was firmly entrenched among China’s most vulnerable cohort. And because the number of infections is so low, few people are immune to catching and beating SARS-CoV-2. According to a 2022 modeling study by researchers at Fudan University in Shanghai, allowing covid to enter and circulate the country at levels high enough to become endemic could lead to a “tsunami” of infections and 1.6 million kill.
5. What is the outlook for the rest of the world?
As most countries have dropped restrictive measures that could stifle the virus, the future will depend on how it develops. Breaking the Omicron variant into a range of suitable new strains could yield more virulent versions capable of evading existing immunity. Some public health experts believe authorities should prepare for this worst case scenario, for example by thoroughly testing wastewater for signs of the virus and detecting its mutations. It is also possible that the evolution of the virus could further reduce its impact. This also applies to the development of more powerful vaccines. If long-term immunization can go beyond protection against serious illness to prevent infection altogether, it could tame Covid. Scientists are working on several new approaches, although they are not expected to reach the market for several years.
More stories like this are available at bloomberg.com