key: cord-1002452-nqd9ci71 authors: Rahimi, Farid; Kamali, Negin; Bezmin Abadi, Amin Talebi title: The Mu strain: the last but not least circulating ‘variant of interest’ potentially affecting the COVID-19 pandemic date: 2021-11-04 journal: Future virology DOI: 10.2217/fvl-2021-0269 sha: ad4f2c87aad0e2386fa17ca2bea2efd0e86b229b doc_id: 1002452 cord_uid: nqd9ci71 nan . Many of the mutations that the Mu variant carries have already been detected among the previous variants of concern (VOCs) with >75% prevalence in at least one lineage. For example, some common mutations in the spike protein (E484K, N501Y, D614G) are shared between the Mu and other VOIs or VOCs (according to the website of the European Centre for Disease Prevention and Control [23] ). T95I has been confirmed in 35.2% of the Delta (B.1.617.2); E484K and N501Y were detected with high frequency in Gamma (P.1) and Beta (B.1.351); N501 in Alpha (B.1.1.7); and D641G in Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2) and Gamma (P.1) VOCs [20, 22] . The Mu variant shares many other mutations with the presently classified VOIs and VOCs (details of the mutations carried by the SARS-CoV-2 variants are available at https://covariants.org/shared-mutations). Such common mutations may enable the Mu lineages to efficiently enter the host cells, evade the immune system or challenge the effectiveness of the presented vaccines. Thus, assessments of the risks associated with the Mu variant may change. Circulating VOIs & VOCs are & will be an ongoing challenge during the pandemic According to WHO, a SARS-CoV-2 lineage qualifies as a VOI if the genetic changes can affect or predictably affect the viral characteristics such as disease severity (virulence); immune, diagnostics or therapeutics evasion; or transmissibility; and cause significant community transmission or multiple clusters in many countries [17] . The VOC qualification; however, includes high transmissibility or detrimental changes in the COVID-19 epidemiology; or high virulence or altered clinical presentations; or a decreased effectiveness of public-health countermeasures or available diagnostics, vaccines or therapeutics [17] . Indeed, VOCs are qualified by one or many of the above characteristics with severe clinical consequences globally. In late August, the Mu VOI was prevailing among 39% of all infected Columbian cases [24] ; this proportion may become higher in other countries. A Japanese group has raised major concerns regarding circulation of the vaccine-resistant SARS-CoV-2 variants [25] , reporting that the Mu lineages are significantly (p = 0.031) resistant to convalescent-serum-mediated neutralization compared with other VOIs or VOCs presently classified [25] . This report has detrimental implications for the naive and fully vaccinated individuals globally if they abandon the public-health countermeasures, including the wearing of face masks, physical distancing and respiratory or manual hygiene. Emergence of the variants also reaffirms the importance of maintaining high-quality ventilation systems inside office towers, high-rise residences, airplanes, office spaces, quarantine facilities and classrooms or lecture rooms. The continuing challenge of the pandemic once more emphasizes the importance of acknowledging the learnt new facts and discarding misinformation about SARS-CoV-2 and its variants [26] . Besides the Mu (B.1.621) variant, four other VOIs have emerged and partially circulated globally. These include Lambda (C.37), Kappa (B.1.617.1), Iota (B.1.526) and Eta (B.1.525) variants. Realistically, the list of VOIs or VOCs involved in the COVID-19 pandemic is not complete yet. Though qualifying the Mu VOI as a VOC may be premature, studying or recording this VOI's (and other VOIs') characteristics including interpersonal transmissibility, virulence, resistance to vaccination and evasion of immunity due to past infections will be valuable for guiding future countermeasures, such as vaccine formulations, during the pandemic. This challenges our present aim of achieving herd immunity by vaccination or past infections. Thus contextually, we postulate that herd immunity may be required realistically against every new SARS-CoV-2 variant that begins or tends to dominate the pandemic statistics in some countries or globally. Thus, opportune and firm consolidated surveillance systems should be implemented globally to monitor and characterize the variants and examine their effects on the present and rapidly administered mass vaccination campaigns globally. This requirement; however, may be challenging in countries that lack capabilities, funding or the appropriate infrastructure for genome sequencing. The Mu strain: the last but not least circulating 'VOI' potentially affecting the COVID-19 pandemic Editorial the 'Mu epicenter' -justifies characterizations of this and other variants by validated mutation-detecting nucleic acid amplification and confirmatory genomic sequencing to corroborate the viral transmission, pathogenesis, epidemiology, clinical features and potential to resist or evade the human immune responses or vaccinations. The collective understanding of, or even doubts about, the new variants can only emphasize that accepting to live with the virus as a 'new normalcy' must not equate to complacence or abandonment of the publichealth countermeasures. This may be challenging in societies that resist wearing masks or with individuals that become complacent or wear inappropriate facemasks. The same challenges are graver in poor countries that strive economically to achieve proper healthcare resources and maintain the countermeasures. Furthermore, accepting and propagating the facts instead of misinformation about SARS-CoV-2, COVID-19 and the pandemic is as fundamental now as it was at the beginning of the pandemic [26] . SARS-CoV-2, SARS-CoV, and MERS-COV: a comparative overview Middle East respiratory syndrome (MERS), influenza, and COVID-19, beyond the lungs: a review article Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): emergence, history, basic and clinical aspects COVID-19) mortality rate COVID-19: study claims real global deaths are twice official figures COVID-19 mortality underreporting in Brazil: analysis of data from government internet portals Economic and psychological impact of COVID-19 lockdown: strategies to combat the crisis. Ind COVID-19: the critical balance between appropriate governmental restrictions and expected economic, psychological and social consequences in Italy. Are we going in the right direction? COVID-19 pandemic and social distancing: economic, psychological, family, and technological effects An early examination: psychological, health, and economic correlates and determinants of social distancing amidst COVID-19 Monitoring the psychological, social, and economic impact of the COVID-19 pandemic in the population: context, design and conduct of the longitudinal COVID-19 psychological research consortium (C19PRC) study The economic impact of the SARS-COV-2 (COVID-19) pandemic in Spain COVID-19 outbreak: migration, effects on society, global environment and prevention The emerging plasticity of SARS-CoV-2 COVID vaccines protect against delta, but their effectiveness wanes Changing composition of SARS-CoV-2 lineages and rise of delta variant in England World Health Organization. Tracking SARS-CoV-2 variants WHO monitoring new coronavirus variant named Mu Viewpoint: Mu variant might escape immunity from vaccines, past infection European Centre for Disease Prevention and Control. SARS-CoV-2 variants of concern as of 16 COVID-19: new Mu variant could be more vaccine-resistant Ineffective neutralization of the SARS-CoV-2 Mu variant by convalescent and vaccine sera COVID-19 lessons learned: a global perspective The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript.