The COVID-19 pandemic may feel like a chapter we’re slowly closing, but the virus continues to evolve, reminding us that the story is far from over. A new variant of the virus, NB.1.8.1, has recently been confirmed in the United Kingdom and is steadily appearing in various parts of the world—including the United States, Australia, Thailand, and parts of Asia and North Africa. First detected in January 2025, the Omicron subvariant has now become a global phenomenon, leading health officials to release new advisories, especially for travelers.NB.1.8.1 is a new sublineage of the Omicron family, which has been the leading group of SARS-CoV-2 variants for several years. While it initially appeared in genetic surveillance data at the beginning of 2025, confirmed cases began to emerge more noticeably by April. It has been officially declared by the World Health Organization (WHO) as a "variant under monitoring," noting its rising rate of detection and susceptibility to avoiding immunity elicited from past infections or vaccination.Today, NB.1.8.1 accounts for around 10.7% of all sequenced infections worldwide. Seven confirmed cases have appeared in Northern Ireland alone in the UK, and experts are monitoring its spread very closely. Its increasing circulation quickly has also brought questions regarding its behavior, contagiousness, and—most particularly—its symptoms.How Does NB.1.8.1 Spread?Following virologists and evidence from GISAID, NB.1.8.1 could have an increased capacity to infect human cells more effectively compared to some of its Omicron ancestors. This doesn't always mean it is more severe, but it will make the variant more infectious, particularly in densely populated indoor environments or areas where immunity is low.The WHO has underscored that variant dynamics have also changed significantly since the start of 2025. Previously prevalent strains such as XEC and LP.8.1 are now being replaced by NB.1.8.1, particularly in places such as China and Hong Kong where this subvariant has rapidly emerged as dominant.What Makes NB.1.8.1 Symptoms Different?Although most symptoms are similar to other COVID-19 strains, the distinguishing factor of NB.1.8.1 is that it is more likely to cause gastrointestinal symptoms. Evidence in the UK and forthcoming international data suggest an uptick in cases presenting with symptoms of:DiarrheaConstipationNausea or vomitingAbdominal pain and bloatingHeartburnThese symptoms, though not entirely novel to COVID-19, are increasingly being reported in NB.1.8.1 cases. This change is leading experts to encourage physicians and patients to be sensitive to digestive complaints that might otherwise be misdiagnosed as foodborne illness or a stomach bug.Recognizing The Unusual Symptoms of NB.1.8.1Besides gastrointestinal distress, the NB.1.8.1 variant may also exhibit a broad spectrum of respiratory and systemic symptoms:High temperature or chillsCoughing that doesn't go awayBreathing that is shortLoss or change of smell and tasteSore throatHeadacheAching of musclesRunny nose or congestionFatigueLoss of appetiteNote that although the occurrence of uncommon gastrointestinal symptoms could be used to distinguish NB.1.8.1, the majority of cases still mimic typical presentations of COVID-19. Therefore, proper diagnosis via testing is still vital.Is the New Variant More Dangerous?To date, there is no indication that NB.1.8.1 causes more serious illness or greater hospitalization than other Omicron subvariants. Nevertheless, its efficiency in spreading and in exhibiting symptoms that will not necessarily lead to COVID testing is a variant to monitor.Immunologists are most interested in how it has the ability to partially evade immunity, something which could cause more breakthrough infections within vaccinated or previously infected people. What Are The Precautions Travelers Must Take?For tourists, particularly to countries with an upsurge of NB.1.8.1 infections such as the US, Australia, Egypt, the Maldives, and Southeast Asia, caution is the word. Although there are no fresh travel restrictions or bans introduced, public health officials suggest a number of precautionary measures:Be aware of local COVID-19 guidelines at your destination.Bring lateral flow tests and masks, especially while moving about airports or using public transportation.Practise diligent hand hygiene and limit time in enclosed or crowded spaces.Consider COVID-specific travel insurance, covering cancellations or health emergencies abroad.Monitor your health and delay travel if symptomatic.Travelers from the UK, in particular, are being urged to remain alert and informed as NB.1.8.1 spreads in popular vacation destinations.Even as COVID-19 has become part of the everyday background, NB.1.8.1 is a reminder that the virus remains in motion. For high-risk groups—the elderly or immunocompromised—the threat is still real, and so is the call for public health awareness.NB.1.8.1 isn't seen as more fatal, but its spreading and uncharacteristic symptoms render it a virus that requires concern, not hysteria. It all comes down to being informed, being aware of symptoms, particularly those that may sense unusual and taking preventative health care when abroad or ill.