#16,662
After two consecutive weeks of reporting increasing COVID cases, this week the WHO reports a decline, although deaths have risen over the past 7-day reporting period. Some of that increase is being attributed to changes in the way COVID deaths are counted in the Americas, and to `retrospective adjustments' to data from India.
While these global numbers have always been considered an `undercount', in recent weeks we have seen a marked reduction in testing around the world, and that undoubtedly skews these numbers even further.
Today's report (#85) contains a strong statement on the declining rate of testing, with the WHO warning: "WHO is concerned about the recent significant reduction in SARS-CoV-2 testing by several Member States. Data are becoming progressively less representative, less timely, and less robust."
The WHO implores member nations to continue with their epidemiological surveillance, and reminds them the pandemic is far from over.
First the overview from this week's report, followed by a brief update on recombinant variants.
Data as of 27 March 2022
Between the end of January and early March 2022, there was a decreasing trend in the number of new COVID-19 cases, which was followed by two consecutive weeks of increases in cases. During the week of 21 through 27 March 2022, the number of new cases declined again with a 14% decrease as compared to the previous week (Figure 1). On the other hand, during the same period, the number of new weekly deaths increased by 43%, likely driven by changes in the definition of COVID-19 deaths in some countries in the Region of the Americas (Chile and the United States of America) and by retrospective adjustments reported from India in the South-East Asia Region.
Across the six WHO regions, over 10 million new cases and over 45 000 new deaths were reported. All regions reported decreasing trends in the number of new weekly cases and four regions reported a decreasing trend in new weekly deaths (Table 1). As of 27 March 2022, over 479 million confirmed cases and over 6 million deaths have been reported globally.
At the country level, the highest number of new weekly cases were reported from the Republic of Korea(2 442 195 new cases; -13%), Germany (1 576 261 new cases; +2%), Viet Nam (1 127 716 new cases; -40%), France (845 119 new cases; +45%), and Italy (503 932 new cases; +6%).
The highest number of new weekly deaths were reported from Chile (11 858 new deaths; +1710%), the United States of America (5 367 new deaths; +83%), India (4 525 new deaths; +619%), the Russian Federation (2 859 new deaths; -22%), and the Republic of Korea (2 471 new deaths; +22%).
The trends reported above should be interpreted with caution as several countries are progressively changing their COVID-19 testing strategies, resulting in lower overall numbers of tests performed and consequently lower numbers of cases detected. Despite a generalized decline in the rate of SARS-CoV-2 testing observed across the six WHO regions, the number of new weekly cases increased again in early to mid-March, indicating that the virus is currently circulating at very high levels.
WHO is concerned about the recent significant reduction in SARS-CoV-2 testing by several Member States. Data are becoming progressively less representative, less timely, and less robust. This inhibits our collective ability to track where the virus is, how it is spreading and how it is evolving: information and analyses that remain critical to effectively end the acute phase of the pandemic.
Decreases in testing, unless done judiciously as part of a strategy aimed at maintaining robust surveillance where it is most impactful, may affect the capacity of countries to identify cases and enable their timely treatment or isolation, and implement other necessary control measures, with the consequent risk of increased spread of SARS-CoV-2.
This may translate in an increase in hospitalizations and deaths, and significant strains on healthcare systems, particularly in areas where public health and social measures have been lifted and where vaccination coverage against COVID-19 is low. Furthermore, reduced testing impacts the capacity of countries to detect emerging variants early, ultimately impairing response efforts.
COVID-19 remains a Public Health Emergency of International Concern, and it is too early to reduce the quality of surveillance. The uncertainty around the characteristics of emerging variants limits our ability to confidently predict the behavior of this disease, as the evolution rate and risk of emerging variants are still high, which could undermine prevention and mitigation measures.
Until we reach the end of the acute phase of the pandemic, countries must maintain sufficient epidemiologic surveillance to inform evidence-based operational decision-making on crucial parameters, including vaccination strategies, vaccine composition, use of therapeutics, and tailored and appropriate public health and social measures.
At this stage of the pandemic, WHO recommends that Member States:
- Continue representative testing financially accessible to all, providing useable and timely epidemiological evidence on the circulation of SARS-CoV-2;
- Focus on early warning and trend monitoring, which could alert to a change in the transmission dynamics of SARS-CoV-2;
- Continue with the daily tracking and reporting of cases and deaths for the duration of the acute phase of the pandemic;
- Monitor severity of COVID-19 in vulnerable groups;
- Enhance genomic surveillance to detect variants, and monitor the evolution of SARS-CoV-2.
Although Omicron BA.2 (including subvariants) has rapidly grown into the dominant strain around the world, we continue to see new variants emerge, including some as the result of recombination (see A COVID Recombination Review).
While most of these variants are destined become evolutionary failures, and will end up as little more than footnotes in the pandemic, the pattern so far with COVID has been that a new variant rises to dominance every 4 to 6 months.
This week's WHO report includes the following brief update on emerging variants, which once again warns on the dangers of reduced testing and sequencing.
Geographic spread and prevalence of VOCs
The current global epidemiology of SARS-CoV-2 is characterized by the global dominance of the Omicron variant. Among the 382 789 sequences uploaded to GISAID with specimens collected in the last 30 days i , 381 824 (99.7%) were Omicron, 175 (<0.1%) were Delta, and 649 sequences were not assigned to a Pango lineage (0.2%).
To note, the global distribution of VOCs should be interpreted with due consideration of surveillance limitations, including differences in sequencing capacities and sampling strategies between countries, as well as delays in reporting. In addition, some countries may have changed their testing and sequencing policies during the presented period.
Recombinant variants
The same process of risk assessment is applied to recombinant variants as for any other emerging variant. Since the epidemiological update published on 22 March 2022, no new evidence indicates that the recombinant variant assigned XD Pango lineage (Delta-Omicron) is associated with higher transmissibility or more severe outcomes.
The XE recombinant (BA.1-BA.2), was first detected in the United Kingdom on 19 January and >600 sequences have been reported and confirmed since. Early-day estimates indicate a community growth rate advantage of ~10% as compared to BA.2, however this finding requires further confirmation.
XE belongs to the Omicron variant until significant differences in transmission and disease characteristics, including severity, may be reported. WHO continues to closely monitor and assess the public health risk associated with recombinant variants, alongside other SARS-CoV-2 variants, and will provide updates as further evidence becomes available.
Since we are now more than 2 years into this pandemic, it is understandable that the public is fatigued, and many countries are eager to declare victory and return to `normal'. The virus appears `milder' now - likely due to vaccines - and fewer people are wearing masks and social distancing.
And maybe we a really are at that turning point. I'd like to believe so. But appearances can be deceiving.
A year ago, the Alpha variant appeared unassailable, and many predicted it would become the endemic strain. Then Delta emerged, and quickly conquered the world. Last November Omicron began to make its move in South Africa, and within 90 days BA.1 had dethroned Delta. And now BA.2 is replacing BA.1.
This pattern has become distressingly familiar.
Everytime we think the pandemic is winding down, COVID reinvents itself. As tempting as it might be to drop our guard and return to `normal', the virus will have the final say on when this pandemic crisis ends.
