An illustration of the Covid-19 virus, created by the U.S. Centers for Disease Control and Prevention. Credit: CDC

WHO warns Covid-19 is “nowhere near over” as Thai genomicists find BA.4 and BA.5 could be more virulent

The organisation’s emergency committee in its latest meeting last Friday agreed that the disease remains a Public Health Emergency of International Concern (PHEIC), the highest alert level issued, citing the inadequacy of surveillance and risk communication amid a continuing rise of cases worldwide. They have recommended governments uphold public and social measures (PHSM) proportionately to the situation

The World Health Organization (WHO) has revealed the latest situation of Covid-19 worldwide this week, saying it is “nowhere near over”. At the press conference in Geneva on Tuesday, WHO Director-General Dr. Tedros Adhanom Ghebreyesus said the disease is “nowhere near over” as he summed up the latest assessment made by the WHO’s emergency committee. 

“I am concerned that the cases of Covid-19 continue to rise, putting further pressure on stretched health systems and health workers. I am also concerned about the increasing trend of deaths. 

“The Emergency Committee on Covid-19 met on Friday last week and concluded that the virus remains a Public Health Emergency of International Concern,” said Dr. Ghebreyesus. 

According to WHO, Covid cases reported to WHO had increased globally by 30% in the last two weeks, largely driven by Omicron BA.4 and BA.5 and other descendent lineages amid the lifting of public health and social measures (PHSM). This increase in cases was translating into pressure on health systems in several WHO regions, its Executive Director on the Health Emergencies Programme, Dr. Michael J. Ryan, remarked. 

Dr. Ghebreyesus continued that the Committee noted their concern about several interlinked challenges. They also made a series of recommendations with several points worth focusing on. Then he said; “New waves of the virus demonstrate again that the Covid-19 is nowhere near over.” 

The chief of the world’s health organisation then encouraged people to push back the virus as it pushes at them. He said people are in a much better position than at the beginning of the pandemic, but this should not be taken for granted. 

“Of course, there’s been a lot of progress. We have safe and effective tools that prevent infections, hospitalizations and deaths. However, we should not take them for granted,” said Dr. Ghebreyesus. He suggested governments deploy tried and tested measures like masking, improved ventilation, and test and treat protocols; review and adjust their Covid-19 response plans based on the current epidemiology; and reverse the reduction in surveillance, testing and sequencing_ all remarked by the Committee. 

“It’s important for governments to focus on boosting those most at-risk communities, finding the unvaccinated so as to build up the wall of immunity toward the 70 percent vaccination target. 

“Planning and tackling Covid-19 should also go hand-in-hand with vaccinating for killer diseases like measles, pneumonia and diarrhea. It’s not a question of either/or, it’s possible to do both,” added Dr. Ghebreyesus. 

Credit: WHO Thailand

Public Health Emergency of International Concern  

At the 12th meeting of the WHO’s International Health Regulations (IHR) Emergency Committee regarding the coronavirus disease, the committee noted that it recognized an overall decoupling of incident cases from severe disease, deaths, to pressure on health systems in the context of increased population immunity.

However, “the Committee unanimously agreed that the Covid-19 pandemic still meets the criteria of an extraordinary event that continues to adversely impact the health of the world’s population and that the emergence and international spread of new variants may present an even greater health impact”, the committee noted as saying in its statement released on Tuesday. 

The committee gave a few critical reasons underpinning their advice to the WHO’s chief as to the event continuing to constitute a PHEIC. 

Firstly, they said there is a recent increase in the growth rate of cases in many countries in different WHO regions. Secondly, the continuing and substantial evolution of the virus is expected to continue in “an unpredictable manner”, they noted.  

“Yet the ability to assess the impact of variants on transmission, disease characteristics, or countermeasures, from diagnostics to therapeutics and vaccines, is becoming increasingly difficult as a result of the inadequacy of current surveillance, including the reductions in testing and genomic sequencing.  

“Additionally, there are uncertainties surrounding the level of readiness of already overburdened health systems across all WHO regions to respond to future Covid-19 pandemic waves,” the committee pointed out. 

The committee then continued on the third reason, saying public health and tools to reduce transmission and disease burden from hospitalisations to long Covid are not being implemented in proportion to local transmission levels or health system capacities. 

Finally, they said there are inadequacies in risk communication and community engagement related to the need for the implementation or adjustment of public and social measures as well as a disconnect in the perception of the risk posed by Covid-19 between scientific communities, political leaders and the general public. 

During their discussion, the committee noted that the virus had not yet established its “ecological niche” and that the implications of a pandemic caused by a novel respiratory virus may not be fully understood.  

Given the current shape and unpredictable dynamics of the pandemic, the committee emphasized the need to reduce the transmission of the virus. This, they noted, requires “the responsible, consistent, and continued use of individual-level protective measures” as well as the continued adjustments of community-wide PHSM to overcome the “all or nothing” binary approaches. 

The committee had particularly expressed concern regarding steep reductions in testing, resulting in reduced coverage and quality of surveillance as fewer cases are being detected and reported to WHO while fewer genomic sequences are being submitted to open access platforms. This, they pointed out, resulted in a lack of representativeness of genomic sequences from all WHO regions, thus impeding assessments of currently circulating and emerging variants of the virus, including the analysis of phenotypic data.  

This in turn is translating into the increasing inability to interpret trends in transmission and to properly inform the adjustments of PHSM, the committee pointed out. 

“The epidemiology of SARS-CoV-2 virus infection remains unpredictable as the virus continues to evolve, through sustained transmission in the human population and in domestic, farmed, and wild animals in which the virus was newly introduced. 

“The Committee noted that both the trajectory of viral evolution and the characteristics of emerging variants of the virus remain uncertain and unpredictable, and in the absence of the adoption of PHSM, the resulting selective pressure on the virus increases the probability of new, fitter variants emerging, with different degrees of virulence, transmissibility, and immune escape potential. 

“For these reasons, the Committee highlighted the need for all States Parties to continue to apply PHSM proportionate to their epidemiological situation, stressing the continued use of effective, individual-level protective measures to reduce transmission,” recommended the committee, adding the PHSM should be adjusted based on estimates of disease prevalence and population protection from infection and vaccination, as well as the capacities of the local health system.  

Last but not least, the committee emphasised the importance of using the lessons learned from the last two and a half years to differentiate the PHSM in individual communities. Given the general public’s perception that the pandemic may be over, the committee stressed the ongoing challenges in communicating that the mitigation of the impact of the ongoing pandemic in the immediate and longer terms depends on the use of PHSM. 

“The Committee acknowledged that any risk communication and community engagement effort should hinge on consistent and synchronized political will, policies, and a concert of community influencers to shift the course of risk perception,” recommended the committee.

Credit: WHO Thailand

More virulent variants? 

The analysis of the latest situation of Covid-19 and a series of recommendations come as Thailand has detected initial signs that the subvariants of BA.4 and BA.5 could be more virulent. 

The Medical Sciences Department early this week released its latest result on genetic sequencing of 570 samples taken early this month. It initially showed a proportion of mild and severe cases of BA.4 and BA.5 infection cases that has cast a negative picture on its virulence. 

According to the department’s chief, Dr. Supakit Sirilak, the number of severe cases caused by BA.4 and BA.5 was higher than that of mild cases in both upcountry and Bangkok. In Bangkok, the number of severe cases caused by BA.4 and BA.5 per that of mild cases stood at 77% (out of 13 samples) per 72% (out of 164 samples). In upcountry, the proportion was similar, with the number of severe cases per that of mind cases standing at 46% (out of 45 samples) per 33% (out of 309 samples).  

Credit: Medical Sciences Department

“It’s a simple math to calculate the growth of severe cases that usually grows along with the increasing number of patients, but when we look at the proportion of severe cases per mind cases, that could suggest the virulence of the virus, and following this latest lab tests, it could be that BA.4 and BA.5 are possibly more virulent than BA.2,” said Dr. Supakit. 

However, Dr. Supakit said it could not pinpoint at this time whether the subvariants are really virulent as more samples are needed for the testing. The department cited a decreasing number of the needed samples following changes in the testing from RT-PCR to ATK. 

He said WHO has not yet reached a conclusion on this issue either, citing its presentation which stated that “currently available evidence does not suggest a difference in disease severity of BA.4 and BA.5 compared to BA.1. 

He additionally cited a recent study on the subvariants’ characteristics in Japan, which has found that they resisted naturally boosted immunity from BA1 and BA.2 infection, and were more efficiently lung infected than BA.2. In a lab test, the study reported that rats were more badly sick by BA.4 and BA.5 than BA.2, Dr. Supakit noted. 

So far, BA.4 and BA.5 have composed almost half of the samples checked, 280 out of 570, with cases in Bangkok continuing to increase from the first 12% to 72% last week, and 6% to 34% in upcountry.  

“They are considered as spreading fast and have started to be taking over BA.2 and BA.1,” said Dr. Supakit. 

The Public Health Ministry, meanwhile, has issued advice to the public during this long holiday, suggesting people uphold self-protective measures including mask-wearing although this is no longer mandatory.