The Black Death (or Bubonic Plague) was one of the most catastrophic pandemics in the world. Its origin is somewhere in Central Asia, which was disrupted by the expansion of the Mongol Empire in the 13th and 14th centuries. Indeed, the pandemic struck China, India, Persia, Syria and Egypt in the early 1340s.The people who gathered on the docks of Messina to welcome the merchant ships saw with dismay that most of the sailors were dead and those who were still alive were seriously ill. It was characterized by large painful buboes (swelling of the lymph nodes), as well as blackened skin patches, high fever and sometimes coughing up blood. The authorities then ordered the ships to return to sea immediately, but it was already too late.

            Many scientists believe that this bacterium spread so rapidly to different communities during the fourteenth century as it morphed in some areas into pneumonic strains, which infected people’s respiratory systems . This enabled the disease to spread more quickly amongst people through cough and sneeze droplets, making it more contagious and deadly. The Black Death spread at a time of growing societal interconnections, including long-distance trade, ironically, facilitated by the Mongols, whose empire extended over 6,000 miles across the Eurasian landmass by the early 1300s. Also, people did not have immunity to this disease. The last outbreak of the plague had occured some 700 years earlier, so for the fourteenth-century Eurasian population, this was a new disease. The earliest recorded outbreak of this disease occurred in Hubei province in Mongol-ruled China, sometime in the early 1330s, before spreading to the rest of China. From there, it travelled in a westerly direction, traversing the major overland and sea trade routes, affecting societies in Central Asia, the ‘Middle East’, and eventually reaching the Mediterranean region by 1347/1348. Once reaching the Mediterranean region, it then travelled by ship to major port cities, such as Cairo, Alexandria, Marseilles, and the Italian city-states, including Venice and Genoa. From these bustling port cities, the disease then ‘proceeded to penetrate almost all of Europe, [North Africa] and the Near East along routes radiating inland from the seaports.

            The outbreak of COVID-19 in December 2019 can be compared to the Black Death in several respects. Although caused by a virus, not a bacterium, COVID-19 is a novel virus for our generation, as the Black Death was for the fourteenth century. Therefore, we have no immunity to this virus. In terms of symptoms, although there remain key differences, interestingly, there are comparisons too. Although COVID-19 presents more like the flu than bubonic plague did, with fever, body aches, a dry cough and nasal congestion amongst other symptoms, the worst cases of COVID-19 have died after experiencing a continuous cough, high fever and difficulty breathing, similar to the pneumonic versions of the plague. Also, similar to pneumonic plague, COVID-19 is transmitted from infected people to others in close proximity, primarily through a cough or sneeze, or by touching contaminated surfaces, where the virus is then absorbed by an uninfected person when they touch their eyes, nose or mouth.

            It is also believed that COVID-19 had its first outbreak in Hubei province, China, where the Black Death began. The first known cluster of cases was traced to an area in the city of Wuhan, with early theories linking it to a ‘wet market’ in this city that sold fresh (including live) species of animals, including exotic species, for consumption and use in traditional medicine preparations. Similar to the Black Death, many believe COVID-19 to be caused by a zoonotic disease spread from infected animals to humans, which has explained the origins of other disease outbreaks in recent years. Presently, the working theory postulates that COVID-19 likely spread from bats and/or pangolins to humans, though this theory has not yet been proven.

            Analogous to the Black Death, COVID-19 circulated within China before spreading elsewhere. During the first few weeks of January 2020, it spread rapidly to neighbouring countries, such as South Korea, Thailand, Japan and Taiwan, and then further afield to the United States. By the end of January, the World Health Organisation (WHO) had declared a global public health emergency, with new cases in Europe, the United Kingdom, Russia, Sweden, and the United Arab Emirates (Taylor 2020). A couple of weeks later, it had reached Egypt and Algeria by 14 and 17 February, respectively; Brazil by 26 February and South Africa by 5 March as a result of infected travellers returning from ‘hotspot’ areas in Asia, Europe and the United States. Unlike the Black Death, which reached most of AfroEurasia via overland and oceanic routes, COVID-19 travelled much more rapidly across the world due to international air travel. On 11 March 2020, the WHO declared COVID-19 a global pandemic.

            To resume, both pandemics had their origins in ‘the East’, devastating communities across Asia and Europe, forcing people into lockdowns and quarantines. It also severely affected the economies of Asia and Europe. But there were differences too. COVID-19 is occurring in an age of digital technologies, which has encouraged a wider awareness of the disease and its impact than only via word of mouth. These similarities and differences also allude to how societies reacted and responded to pandemics in diverse geopolitical settings, in different times and space. But, what about variant ?

            The COVID-19 virus variant. All viruses – including SARS-CoV-2, the virus that causes COVID-19 – evolve over time. When a virus replicates or makes copies of itself, it sometimes changes a little bit, which is normal for a virus. These changes are called “mutations”. A virus with one or more new mutations is referred to as a “variant” of the original virus. When a virus is widely circulating in a population and causing many infections, the likelihood of the virus mutating increases. The more opportunities a virus has to spread, the more it replicates – and the more opportunities it has to undergo changes. Most viral mutations have little to no impact on the virus’s ability to cause infections and disease. But depending on where the changes are located in the virus’s genetic material, they may affect a virus’s properties, such as transmission (for example, it may spread more or less easily) or severity (for example, it may cause more or less severe disease).

            What impact do the new variants of the COVID-19 virus have on vaccines? The COVID-19 vaccines that are currently in development or have been approved are expected to provide at least some protection against new virus variants because these vaccines elicit a broad immune response involving a range of antibodies and cells. Therefore, changes or mutations in the virus should not make vaccines completely ineffective. In the event that any of these vaccines prove to be less effective against one or more variants, it will be possible to change the composition of the vaccines to protect against these variants. Data continues to be collected and analysed on new variants of the COVID-19 virus. WHO is working with researchers, health officials and scientists to understand how these variants affect the virus’s behaviour, including their impact on the effectiveness of vaccines, if any. See WHO’s Disease Outbreak News to get up-to-date information on the impact of COVID-19 virus variants on the effectiveness of the different vaccines. This is an area where the evidence remains preliminary and is developing quickly. While we are learning more, we need to do everything possible to stop the spread of the virus in order to prevent mutations that may reduce the efficacy of existing vaccines. In addition, manufacturers and the programmes using the vaccines may have to adjust to the evolution of the COVID-19 virus: for example, vaccines may need to incorporate more than one strain when in development, booster shots may be required, and other vaccine changes may be needed. Trials must also be designed and maintained to allow any changes in efficacy to be assessed, and must be of sufficient scale and diversity to enable clear interpretation of results. Studies of the impact of vaccines as they are deployed are also essential in order to understand their impact.

            What is WHO doing to monitor and understand the impact of virus variants on the efficacy of COVID-19 vaccines? WHO has been tracking mutations and variants since the start of the COVID-19 outbreak. Our global SARS-CoV-2 laboratory network includes a dedicated Virus Evolution Working Group, which aims to detect new changes quickly and assess their possible impact. Research groups have carried out genomic sequencing of the COVID-19 virus and shared these sequences on public databases, including GISAID. This global collaboration allows scientists to better track how the virus is changing. WHO recommends that all countries increase the sequencing of the COVID-19 virus where possible and share data to help one another monitor and respond to the evolving pandemic. WHO has also established a SARS-CoV-2 Risk Monitoring and Evaluation Framework to identify, monitor and assess variants of concern. It will involve components like surveillance, research on variants of concern, and evaluation of the impact on diagnostics, therapeutics and vaccines. The framework will serve as a guide for manufacturers and countries on changes that may be needed for COVID-19 vaccines.

            How can we prevent future new variants of the COVID-19 virus? Stopping the spread at the source remains key. Current measures to reduce transmission – including frequent hand washing, wearing a mask, physical distancing, good ventilation and avoiding crowded places or closed settings – continue to work against new variants by reducing the amount of viral transmission and therefore also reducing opportunities for the virus to mutate. Scaling up vaccine manufacturing and rolling out vaccines as quickly and widely as possible will also be critical ways of protecting people before they are exposed to the virus and the risk of new variants. Priority should be given to vaccinating high-risk groups everywhere to maximize global protection against new variants and minimize the risk of transmission. Moreover, ensuring equitable access to COVID-19 vaccines is more critical than ever to address the evolving pandemic. As more people get vaccinated, we expect virus circulation to decrease, which will then lead to fewer mutations.

            Why is it important to get vaccinated even if there are new variants of the virus? Vaccines are a critical tool in the battle against COVID-19, and there are clear public health and lifesaving benefits to using the tools we already have. We must not put off getting vaccinated because of our concerns about new variants, and we must proceed with vaccination even if the vaccines may be somewhat less effective against some of the COVID-19 virus variants. We need to use the tools we have in hand even while we continue to improve those tools. We are all safe only if everyone is safe.

by

Xander B. ©

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