Nigeria Centre for Disease Control (NCDC) and Prevention has said that the COVID-19 Omicron sub-lineages partly responsible for the current increase in COVID-19 cases in China, the United States, and the United Kingdom have not yet been detected in the country.
The NCDC disclosed this on Wednesday in an update on COVID-19 genomic surveillance signed by its Director General, Dr Ifedayo Adetifa.
The update which was made available to our correspondent showed that the Omicron sub-lineage responsible for the rise in cases in the US and UK is XBB.1.5 while BF.7 is responsible for the increased cases in China.
Adetifa, however, said B.5.2.1 has been seen in Nigeria since July 2022.
According to him, country-targeted travel restrictions including requests for PCR-negative tests from incoming travellers had little or no effect on preventing global and national circulation of omicron since the emergence of the variant and its relatives with their shorter incubation period.
The NCDC-led COVID-19 Emergency Operations Centre is monitoring COVID-19 trends in China, the United States of America, the United Kingdom, South Africa, India, and other countries with a high volume of traffic to and from Nigeria. This includes the resurgence of COVID-19 in China following the relaxation of the country’s zero-COVID policy, as well as significantly increased COVID-19 cases, admissions, and deaths in the UK and the USA over the past weeks driven in part by the usual winter exacerbations of respiratory illnesses.
Before the recent case increase in China, the USA, the UK, and other countries, genomic surveillance has shown that the Omicron SARS-CoV-2 variant and its lineages continue to dominate in recorded infections worldwide. However, the rise in the new Omicron sub-lineages XBB.1.5 in the UK and the US, and BF.7 in China raises concern as it may spread faster than older Omicron sub-lineages (e.g., XBB or BQ) and that they are responsible in part for current increases in cases, hospitalisations, and deaths. However, the sub-lineage seen with cases in China, B.5.2.1, and BF.7 are responsible for the surge in China and do not appear to be increasing unusually in other countries.
The NCDC continues to strengthen genomic surveillance of the COVID-19 virus in Nigeria. Since the detection of the Omicron variant in December 2021, its sub-lineage (BQ.1/BQ.1.1) has been dominant in Nigeria. None of these dominant sub-lineages in Nigeria that are also circulating elsewhere has been associated with any increases in case numbers, admissions, or deaths locally.
The sub-lineages partly responsible for the current increase in COVID-19 cases in other countries i.e., XBB.1.5 and BF.7 have not yet been detected in the country but B.5.2.1 has been seen here since July 2022 and the others are most likely here already. BF.7 and XBB have also been circulating in South Africa since October 2022 but without any accompanying increase in cases, severe illness, or deaths.
Regardless of COVID-19 variants in different parts of the world, severe disease, admissions, and deaths disproportionately affect the unvaccinated and those with established risk factors i.e., older people, people with co-morbidities, and the immunocompromised. The most important action for Nigerians to take is to get vaccinated against COVID-19 as the vaccine is the most important intervention for preventing severe disease, hospitalisation, and death.
Though the COVID-19 protocols and restrictions have been eased, people at high risk for severe COVID-19 are advised to continue to adhere to the recommended non-pharmaceutical interventions such as the use of face masks, good hand and respiratory hygiene and avoidance of crowded spaces.
COVID-19 has and continues to follow a different epidemiological course in Nigeria and most of Africa. Other Omicron sub-lineages that were associated with increases in cases, admissions and deaths elsewhere did not cause the same in Nigeria as confirmed by our genomics surveillance. This is because the population is significantly protected from a combination of natural immunity and vaccination with vaccines with a high impact on hospitalisation, and deaths. In hindsight, country-targeted travel restrictions including requests for PCR-negative tests from incoming travellers had little or no effect on preventing global and national circulation of omicron since the emergence of this variant and its relatives with their shorter incubation period.
The NCDC will continue to pay close attention to the ongoing COVID-19 situation in other countries and gather additional surveillance data to inform actions. We are reviewing the situation again this week. At this next review and if deemed necessary, a range of actions, not limited to enhanced surveillance of travellers at airports, may be decided on and implemented.