Flu vs RSV vs COVID-19 in 2025: Symptoms, Structures, and abinScience Reagents for Virology Research

Influenza (Flu)

Introduction

Influenza, caused by Influenza A and B viruses (Orthomyxoviridae), is a highly contagious respiratory illness. The 2025 H3N2 strain dominates in Singapore and Japan, causing sudden fever (>38.5°C), muscle aches, headache, fatigue, and dry cough. Severe cases lead to pneumonia, with Japan reporting ~287 hospitalizations by October 10, 2025. The 2025-2026 flu vaccine targets A/Victoria/4897/2022 (H1N1)pdm09-like, A/Croatia/10136RV/2023 (H3N2)-like, and B/Austria/1359417/2021 (Victoria lineage)-like (egg- and cell-based versions differ slightly); historical data suggest 40-60% efficacy with good strain matching, though 2025 VE is under evaluation.

Protein and Genomic Structure

Influenza viruses have 8 RNA segments (~13.5 kb) encoding key proteins: Hemagglutinin (HA) for cell entry, Neuraminidase (NA) for virus release, and Matrix proteins (M1/M2) for virion structure. NS1 aids immune evasion by suppressing interferon responses.

Viral Pathogenicity Factors

HA binds sialic acid receptors to infect respiratory cells, while NA facilitates viral release. NS1 triggers cytokine storms, exacerbating inflammation, particularly with H3N2 in 2025. High transmissibility via droplets and contact fuels rapid spread in Japan’s schools and Singapore’s urban settings.

Key Research Targets: HA, NA, NS1

Respiratory Syncytial Virus (RSV)

Introduction

RSV (Paramyxoviridae), an enveloped RNA virus, causes severe respiratory illness in infants and the elderly. Symptoms include runny nose, cough, wheezing, and poor appetite, with risks of bronchiolitis or pneumonia. In Singapore and Japan, RSV surges in cooler months, with infants under 6 months and adults over 60 at high risk. Nirsevimab and RSV vaccines are critical for research and prevention studies.

Protein and Genomic Structure

RSV’s ~15 kb RNA encodes Fusion (F) and Attachment (G) glycoproteins for cell entry and NS1/NS2 proteins for immune suppression. The F protein drives membrane fusion, forming syncytia in infected airways.

Viral Pathogenicity Factors

The F protein forms syncytia, obstructing airways, while NS1/NS2 evade interferon responses, worsening inflammation in infants. High transmissibility via droplets and contact makes RSV a major concern in Japan’s daycare centers and Singapore’s elderly care facilities.

Key Research Targets: RSV F, RSV G

SARS-CoV-2

Introduction

SARS-CoV-2 (Coronaviridae) remains a global threat in 2025, with Omicron variants driving cases in Singapore and Japan. Symptoms include fever, dry cough, and fatigue; olfactory/taste loss occurs in ~10-20% of 2025 cases (lower than early variants). Severe cases lead to pneumonia, with long COVID affecting ~6-10% of all cases and 10-30% of hospitalized patients. Updated vaccines and antivirals like Paxlovid are key for research and management.

Protein and Genomic Structure

SARS-CoV-2’s ~30 kb RNA encodes Spike (S), Envelope (E), Membrane (M), and Nucleocapsid (N) proteins. The Spike protein’s receptor-binding domain (RBD) binds ACE2 receptors, while Nsp1-16 support viral replication.

Viral Pathogenicity Factors

Spike binds ACE2, enabling multi-organ infection. Cytokine storms and blood clotting contribute to severe outcomes and long COVID. High aerosol and droplet transmissibility drives outbreaks in Singapore’s urban centers and Japan’s public transport systems.

Key Research Targets: Spike, RBD, Nsp12

Why Choose abinScience?

abinScience supports virology research with high-quality tools for studying Flu, RSV, and COVID-19:

• Validated antibodies for ELISA, Western Blot, and immunofluorescence
• High-purity recombinant proteins (e.g., SARS-CoV-2 Spike, RSV F)
• ELISA kits for flu, RSV, and COVID-19 detection
• Reagents like PCR primers and virus lysis buffers
• Custom services for antibody and protein development

Key Products: Spike Protein/Antibodies, RSV F Protein, Influenza HA