Why COVID-19 cases are rising in Singapore again: LF.7 and NB.1.8 explained

Why Are COVID-19 Cases Rising in Singapore Again in May 2025?

Singapore has reported a sharp 28% week-on-week rise in COVID-19 cases, with infections climbing from 11,100 to 14,200 in the week ending May 3, 2025. This uptick has raised public health concerns across the island city-state, especially as hospitalizations also increased—from a daily average of 102 to 133. Although the number of patients requiring intensive care unit (ICU) support has marginally declined from three to two cases per day, the overall spike in infections marks the most significant resurgence since late 2023.

Authorities have confirmed that the surge is largely driven by two emerging SARS-CoV-2 variants—LF.7 and NB.1.8—both of which are descendants of the JN.1 lineage. These variants currently account for more than two-thirds of all sequenced cases in Singapore, yet experts say they do not appear to be more transmissible or severe than previous dominant strains.

What Are LF.7 and NB.1.8 Variants and Why Are They Dominant Now?

LF.7 and NB.1.8 belong to the JN.1 genetic family, itself an evolution of the Omicron strain. These offshoots have gained prevalence across parts of Asia due to their apparent ability to slightly evade prior immunity and establish dominance in post-Omicron populations. In Singapore, these variants have overtaken older lineages not because of significantly higher transmissibility or disease severity, but due to a combination of immune waning and behavioral patterns such as increased social interaction.

While the Ministry of Health is tracking variant developments closely, it has emphasized that there is no current evidence suggesting LF.7 or NB.1.8 lead to more severe clinical outcomes. This aligns with the observed data—hospitalization numbers are rising, but critical cases remain relatively rare.

Why Is Immunity Waning Among the Population?

One of the key reasons behind the resurgence is the natural decline in population-level immunity. Although Singapore maintains one of the highest vaccination rates globally, immunity—especially from earlier rounds of vaccines or natural infections—declines over time. This leaves certain demographic groups, particularly older adults and individuals with comorbidities, more vulnerable to infection.

Public health officials have urged residents aged 60 and above, those with underlying medical conditions, and people living in aged care facilities to receive an additional booster dose if it has been more than 12 months since their last vaccination. The current booster campaign focuses on ensuring high uptake ahead of the mid-year transmission season.

What Are the Symptoms of the Current COVID-19 Wave?

Patients infected during this wave are exhibiting a broader spectrum of symptoms compared to earlier outbreaks. In addition to common symptoms such as fever, cough, and sore throat, many are also reporting nausea, vomiting, fatigue, brain fog, and conjunctivitis. These less specific symptoms can delay diagnosis and increase the risk of community spread.

The Ministry of Health has issued guidance advising symptomatic individuals to stay home, wear masks if they must go out, and limit interaction with high-risk groups. The goal is to prevent uncontrolled transmission, especially in households with elderly members or those with chronic illnesses.

How Is Singapore’s Healthcare System Responding to the Surge?

Singapore’s healthcare infrastructure has thus far handled the increased load effectively. Hospital capacity remains adequate, with no major signs of strain on intensive care units or emergency departments. Authorities have credited this resilience to the combination of continued vaccination, public health awareness, and early outpatient intervention protocols.

Hospitals have not yet triggered emergency preparedness plans, but have been asked to remain on alert should the current wave persist or escalate. Contingency resources, including step-down care facilities and rapid testing infrastructure, are being kept ready to absorb any potential future spike.

What Public Health Measures Are Currently in Place?

Unlike during earlier waves, no lockdowns or sweeping restrictions have been reintroduced. Singapore is adopting a calibrated approach, focusing on public education, targeted vaccine outreach, and advisory-based behavioral modifications. Key recommendations include maintaining good hand hygiene, using masks in crowded spaces, and staying home when unwell.

Employers have been encouraged to allow remote work for staff with flu-like symptoms. Schools and care institutions have also been asked to reinforce their outbreak management protocols, including cohorting strategies and ventilation audits.

How Does This Compare With Past COVID-19 Waves in Singapore?

The current situation, while notable, is less severe than previous waves. At the height of the Omicron BA.5-driven wave in 2022, daily cases exceeded 20,000 and ICU utilization was significantly higher. This time, although infections have risen rapidly, the clinical severity remains low, pointing to effective immunity within the population—likely due to a combination of vaccine protection and prior exposure.

Experts describe this phase as part of the broader endemic transition, where SARS-CoV-2 causes periodic surges but is unlikely to result in healthcare system collapse unless compounded by a major new variant.

Is This a Singapore-Only Trend or Part of a Regional Pattern?

The surge in Singapore is part of a wider trend affecting parts of Asia. In Hong Kong, COVID-19 test positivity rates climbed from 6.2% to 13.6% within a month. Thailand has also observed an uptick in hospital admissions linked to similar JN.1 offshoots.

Regional virologists believe this wave is cyclical, likely triggered by seasonality, mobility, and immune decline rather than a mutation of high concern. No new global variants have been classified as variants of interest or variants of concern by the World Health Organization as of mid-May 2025.

What Should Singapore Residents Do Now?

Residents are urged to remain cautious but not panic. Staying up to date with vaccinations is the most important preventive measure, followed by practicing personal hygiene and self-isolating when symptomatic. Health authorities are also encouraging employers and institutions to revisit flexible work and learning arrangements where feasible.

For vulnerable individuals, especially seniors, early access to antivirals and booster scheduling are key. The broader public is advised to treat COVID-19 with the same level of seriousness as seasonal influenza—neither trivializing it nor succumbing to fear.

What’s the Outlook for Singapore’s COVID-19 Situation?

Singapore’s COVID-19 surge, though notable, remains manageable. Experts believe that with ongoing public cooperation and proactive vaccination, the wave will plateau without overwhelming hospitals. However, authorities warn that complacency could invite more serious consequences, especially if compounded by an international variant of concern.

The next few weeks will be critical in determining whether the current wave stabilizes or continues to rise. Meanwhile, Singapore is expected to maintain its stance on preparedness rather than panic, focusing on mitigation through measured steps and community engagement.