Top 20 Best-Selling Infectious Disease Drugs Dominating in 2025

As global attention continues to be focused on pandemic preparedness, antimicrobial resistance and vaccine-driven disease prevention, infectious disease therapies remain at the forefront of pharmaceutical innovation and commercial success.

In 2024, leading drugmakers like Gilead, Pfizer, Merck and GSK saw billions in revenue from vaccines and antivirals targeting HIV, COVID-19, HPV, RSV, shingles, pneumonia and other serious infections.

While some therapies, like HIV frontrunner Biktarvy and HPV vaccine Gardasil, maintained strong momentum, others, namely COVID-19 treatments like Paxlovid and Veklury, faced headwinds due to declining pandemic-era demand.

In this blog, we highlight the top 20 best-selling infectious disease drugs of 2024, analyzing their financial performance and what to expect in 2025.

When it comes to companies that report in foreign currencies, the conversion to US dollars uses the average annual exchange rates reported by the US Federal Reserve.

Related: Top 5 Best-Selling Respiratory Disease Drugs to Watch in 2025

1. Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide)

Indication(s): HIV

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $13.42 billion

2025 Outlook: Gilead’s flagship HIV treatment Biktarvy was the world’s highest‑selling infectious disease drug in 2024, generating approximately $13.42 billion in global sales, a 13% year‑over‑year increase, and making up more than half of Gilead’s HIV revenue. In the fourth quarter alone, Biktarvy’s sales rose 21% to $3.8 billion, reinforcing its position as the leading HIV regimen in the US and other major markets. The surge was primarily driven by heightened demand, favorable inventory dynamics and higher average realized prices. The fixed‑dose combination drug had strong uptake as a first‑line therapy, underscoring its central role in Gilead’s portfolio. As a once‑daily integrase inhibitor and reverse transcriptase inhibitor combo, it has become the regimen of choice in many treatment guidelines, commanding more than 50% of the US HIV market. The drug’s success significantly contributed to Gilead’s total HIV product sales, which reached $19.6 billion in 2024, an 8% increase over 2023.

2. Gardasil (Gardasil 9, HPV vaccine)

Indication(s): HPV

Manufacturer(s): Merck

2024 Sales (USD): $8.58 billion

2025 Outlook: Merck’s HPV vaccines Gardasil/Gardasil 9 generated $8.6 billion in global sales in 2024, marking a ~2% year-over-year decline (or ~3% in constant currency) due to weak demand in China. As a result, Merck paused Gardasil shipments to China in Q4 to allow inventory normalization. Despite the China lull, Gardasil sales grew at double-digit rates in most other regions. For 2025, Merck suspended its long-term $11 billion sales target for Gardasil amid China uncertainties and broader consumer softness, and has signaled more modest growth expectations. Despite the uncertainties, Gardasil remains Merck’s second-largest revenue-generating product. In January 2025, Merck also received expanded approval in China for Gardasil in males aged nine to 26 years, making it the first HPV vaccine approved in China for this group, which could revive some demand in the country.

3. Comirnaty (tozinameran)

Indication(s): COVID-19

Manufacturer(s): Pfizer/BioNTech

2024 Sales (USD): $7.79 billion

2025 Outlook: In 2024, Pfizer’s COVID‑19 vaccine Comirnaty, jointly developed with BioNTech, generated approximately $7.79 billion in global sales, with Pfizer’s share amounting to $5.35 billion. Despite a 38% operational decline in Q4 and a 53% drop in annual sales compared to the previous year, influenced by significant reductions in vaccination rates and lower contracted volumes, Comirnaty remained a significant contributor to Pfizer’s portfolio. BioNTech reported total revenues of €2.75 billion ($2.98 billion) in 2024, down 27% from the prior year due to the declining demand for the vaccine, its sole commercial product. The decline was compounded by inventory write-downs and a reduced share of gross profits from its collaboration with Pfizer, leading to BioNTech’s first annual net loss since 2019. Overall, Pfizer expects Comirnaty sales in 2025 to be broadly muted relative to 2024, reflecting stabilization in COVID‑related immunization demand as part of their $61 billion to 64 billion revenue guidance. However, continued global booster campaigns and durable brand recognition are expected to support some sustained uptake through the year.

4. Prevnar family (pneumococcal conjugate vaccines)

Indication(s): Pneumonia

Manufacturer(s): Pfizer

2024 Sales (USD): $6.41 billion

2025 Outlook: In 2024, the broader Prevnar family, including Prevnar 20/Apexxnar and Prevnar 13, generated approximately $6.41 billion in vaccine revenue, growing around 7% operationally year-over-year, driven by increased pediatric uptake in the US and adult adoption in international markets. The vaccines protect against pneumococcal disease across all age groups and form a core part of immunization schedules worldwide. While Pfizer didn’t disclose Prevnar 20‑specific revenue, the 20‑valent vaccine played a central role in this growth, particularly in expanding adult immunization programs. Pfizer is positioned to capitalize on updated CDC recommendations released in October 2024, which expanded routine pneumococcal vaccination to all adults aged 50 and older. Meanwhile, competition from newly approved vaccines such as Merck’s Capvaxive (PCV21) is expected to intensify, but continued updates and expansions of serotype coverage will help sustain adoption.

5. Paxlovid (nirmatrelvir/ritonavir)

Indication(s): COVID-19

Manufacturer(s): Pfizer

2024 Sales (USD): $5.72 billion

2025 Outlook: In 2024, Pfizer’s COVID‑19 antiviral Paxlovid generated approximately $5.72 billion, accounting for about 9% of the company’s total revenue and ranking it as the company’s third highest-selling product for the year. Its reported revenue included a $1.2 billion one-time gain, consisting of a $771 million government adjustment and a $442 million fulfillment to the US Strategic National Stockpile, which inflates year-over-year comparisons. In 2025, Pfizer expects COVID-19 product revenues, including Paxlovid, to remain broadly flat operationally, excluding 2024’s non-recurring items. Paxlovid sales are anticipated to decline around 25% year-over-year due to waning COVID-19 demand and diminishing government purchases. Despite this, the drug remains a material contributor to Pfizer’s portfolio, though its relative share is expected to experience a drop.

6. Shingrix (herpes zoster vaccine)

Indication(s): Shingles

Manufacturer(s): GSK

2024 Sales (USD): $4.30 billion

2025 Outlook: In 2024, GSK’s shingles vaccine Shingrix earned approximately £3.36 billion ($4.30 billion), reflecting a modest 1% increase year-over-year increase and outperforming the company’s broader vaccine segment, which declined by about 4%. The growth was largely driven by strong international demand, particularly in Europe and Australia. In 2024, markets outside the US accounted for 56% of Shingrix’s global sales, up from 45% in 2023, following its launch in 52 countries. US sales fell 18%, driven by a slower pace of vaccinating unprotected populations and changes in pharmacy reimbursement under new CMS rules. GSK is also studying the co-administration of Shingrix with other vaccines, including seasonal flu and its RSV vaccine, Arexvy. New data last year showed Shingrix can be safely given with Arexvy, with further studies underway to assess co-administration with pneumococcal vaccines as well. In 2025, GSK anticipates overall vaccine sales to decline modestly (low single-digit percentage), though Shingrix may remain relatively stable due to its high penetration in existing adult immunization programs and sustained uptake in markets outside the US.

7. Dovato (dolutegravir/lamivudine)

Indication(s): HIV

Manufacturer(s): ViiV Healthcare, a joint venture majority-owned by GSK, along with Pfizer and Shionogi

2024 Sales (USD): $2.79 billion

2025 Outlook: Dovato remains the largest product in ViiV’s HIV portfolio, supported by strong demand and favorable market performance. ViiV holds the second-largest share of the global HIV therapy market at approximately 32%, trailing only Gilead, which dominates with Biktarvy at 51%. Dovato stands as the leading two-drug regimen in the HIV treatment landscape, and ViiV anticipates continued growth in its oral two-drug portfolio, even as it expands its long-acting treatment offerings. The company posted positive long-term readouts for Dovato recently. Results from the Phase IIIb PASO DOBLE trial showed Dovato matched the efficacy of three‑drug regimens (e.g., Biktarvy) while demonstrating significantly lower weight gain, a meaningful differentiator for many patients. Real‑world data from the DOLCE study indicate Dovato delivers comparable viral suppression to three-drug therapies, even in individuals with advanced HIV. In the Phase IIIb VOLITION study, 89% of treatment-naïve individuals with HIV who achieved rapid viral suppression on oral Dovato chose to switch to the long-acting injectable regimen Vocabria + Rekambys (cabotegravir + rilpivirine LA), citing greater convenience and reduced risk of missed doses. This highlighted Dovato as an efficacious and potentially better-tolerated option for long‑term HIV maintenance therapy.

8. ProQuad (measles, mumps, rubella and varicella virus vaccine)

Indication(s): Active immunization for prevention of measles, mumps, rubella and varicella in children

Manufacturer(s): Merck & Co., Inc.

2024 Sales (USD): $2.49 billion

2025 Outlook: Although recent sales dipped, ProQuad continues to play a key role in pediatric immunization. Its integration into routine vaccination schedules and potential renewed demand during outbreak responses suggest continued relevance, pending stabilization of supply dynamics and resumed restocking of national stockpiles. ProQuad generated about $539 million in Q1 2025, a 5% decline from the same quarter in 2024, attributed largely to the US using its pediatric vaccine stockpile amid measles outbreaks. Monovalent varicella vaccines dominate the varicella market, which was valued at $3.4 billion in 2024, and are favored for cost-efficiency and ease of procurement in public programs. Combination vaccines like ProQuad are less prevalent.

9. Beyfortus (nirsevimab)

Indication(s): RSV

Manufacturer(s): AstraZeneca and Sanofi

2024 Sales (USD): $2.28 billion

2025 Outlook: Beyfortus is a long-acting monoclonal antibody (LAAB) developed by AstraZeneca and commercialized in partnership with Sanofi. In its first full year on the market since its July 2023 approval, Beyfortus achieved blockbuster status with over $2 billion in global sales. Continued growth is expected, supported by increased manufacturing capacity and accelerated global distribution ahead of the 2025-2026 RSV season. Sanofi reports having tripled production capacity and doubled manufacturing sites since its launch to address supply with the anticipated increase in demand. Unlike AstraZeneca’s Synagis (palivizumab), which requires monthly injections throughout the RSV season, nirsevimab offers single-dose, season-long protection thanks to a modified Fc fragment that extends its half-life. It also achieves similarly robust efficacy and safety across the infant population. AstraZeneca reported that in its first year of use, it showed strong real-world effectiveness, reducing RSV-related hospitalizations by up to 90% across several countries.

10. Descovy (emtricitabine/tenofovir alafenamide)

Indication(s): HIV

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $2.11 billion

2025 Outlook: In 2024, Descovy generated approximately $2.1 billion in sales, an increase of about 6% over 2023, driven by higher demand, though somewhat offset by slightly lower average realized prices. In the fourth quarter, it achieved around $616 million, up 21% year-over-year, supported by favorable inventory dynamics and pricing trends. Despite intensifying competition in the HIV market and continued dominance of Gilead’s flagship regimen Biktarvy, Descovy currently remains a steady contributor to the company’s HIV portfolio, particularly as a backbone therapy in combination regimens and for its use in PrEP. However, its contribution is expected to gradually diminish amid competitive pressures from long-acting injectable therapies and generic encroachment. In 2025, Gilead expects HIV sector revenues to remain relatively stagnant overall, with Descovy hovering at the $2 billion mark. This is due to ongoing demand being potentially balanced by reimbursement changes under Medicare Part D and channel mix shifts i.e., changes in the distribution of drug sales across channels (e.g., retail, specialty, hospital, government).

11. Veklury (remdesivir)

Indication(s): COVID-19

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $1.80 billion

2025 Outlook: In 2024, Veklury sales declined approximately 18% year-over-year to $1.8 billion, reflecting reduced COVID‑19 hospitalizations globally amid increased vaccination and therapeutic options. In Q4 alone, sales plunged 53% to $337 million compared to Q4 2023, driven by continued weakening demand. Sales are projected to continue their downward trend in 2025 as global COVID-19 hospitalization rates decline and treatment demand normalizes. Gilead projects Veklury revenues of around $1.4 billion this year, reflecting reduced pandemic-related purchasing and increased competition from alternative antivirals and preventive measures. Nevertheless, sustained usage in hospital settings as part of COVID‑19 treatment protocols will continue.

12. Genvoya (elvitegravir/cobicistat/emtricitabine/tenofovir)

Indication(s): HIV

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $1.76 billion

2025 Outlook: Genvoya remains a cornerstone in HIV therapy due to its convenience as a single-tablet regimen and improved safety profile (thanks to tenofovir alafenamide). However, it faces increasing competition from newer agents like Biktarvy and Descovy, which may dampen its near-term growth. Sales in 2024 dipped from just over $2 billion in 2023 to $1.76 billion in 2024. Pricing pressures, potential patent expirations and evolving treatment guidelines will be key to its trajectory through 2025. Gilead’s official filings indicate that Genvoya’s latest patent is set to expire in 2029 in the US and 2028 in the EU. Gilead’s HIV portfolio demonstrates a pattern of shifting patients to newer therapies like Biktarvy to preempt generic erosion. This strategic migration has helped sustain overall HIV franchise value and resilience. While Genvoya will likely maintain baseline demand, its growth trajectory is expected to plateau amid internal competition from Gilead’s newer regimens. Continued preferential prescribing of Biktarvy and Descovy, alongside Gilead’s robust deployment of lifecycle strategies, is anticipated to moderate Genvoya’s contribution, but the drug should continue generating steady revenue through 2025.

13. Prezista (darunavir/cobicistat)

Indication(s): HIV

Manufacturer(s): Janssen and Gilead Sciences

2024 Sales (USD): $1.71 billion

2025 Outlook: Prezista is a key part of the global darunavir market, which was valued at around $1.89 billion in 2024, with a projected increase to around $2.34 billion by 2030, indicating moderate growth at a compound annual growth rate (CAGR) of ~3.6%. Sales were down 7.7% from $1.85 billion in 2023 to $1.71 billion in 2024. A couple of Darunavir generics were approved in the US recently from Amneal and Annora Pharma in late 2023 and early 2025, respectively. As patents expire and generics enter, Prezista’s sales may face headwinds. However, its established presence and role in second-line regimens could sustain residual demand in markets where alternatives like integrase inhibitors are not yet accessible.

14. Tivicay (dolutegravir)

Indication(s): HIV

Manufacturer(s): ViiV Healthcare, a joint venture majority-owned by GSK, along with Pfizer and Shionogi

2024 Sales (USD): $1.68 billion

2025 Outlook: Tivicay remains a foundational regimen for HIV treatment due to its high efficacy and tolerability. However, its US and global growth is facing mounting pressure as two-drug regimens gain traction and erode market share from older, three-drug regimens. Tivicay sales declined in 2024 as ViiV Healthcare’s HIV portfolio shifted toward the oral two-drug regimens Dovato and Juluca, which now account for 42% of total sales. According to GSK, Dovato, a dolutegravir-based two-drug therapy and the company’s top-selling product, continued to expand globally across the US, Europe, Japan, Australia and other markets. This growing adoption of streamlined regimens contributed to reduced demand for older treatments like Tivicay and Triumeq, the company said in its 2024 annual report. The core patent for dolutegravir is slated to expire in October 2027, with related form patents extending through December 2029. Multiple sources estimate that generic versions may not reach the market until as late as June 2030 due to patent litigation and exclusivity strategies. As generic entry looms, ViiV is strategically shifting patients toward newer formulations and combination therapies that bundle dolutegravir with other agents, both to preserve market share and soften potential revenue erosion. Tivicay is expected to deliver stable, modest declines in revenue, primarily due to internal cannibalization from newer regimens like Dovato and continued competition from more streamlined HIV therapies. Nonetheless, residual demand, particularly in treatment-experienced populations and regions where access remains critical, should sustain a baseline revenue stream throughout 2025.

15. Triumeq (abacavir/dolutegravir/lamivudine)

Indication(s): HIV

Manufacturer(s): ViiV Healthcare, a joint venture majority-owned by GSK, along with Pfizer and Shionogi

2024 Sales (USD): $1.65 billion

2025 Outlook: Triumeq continues to benefit from global demand for simplified, effective antiretroviral therapies. As a triple-drug, single-tablet regimen, Triumeq remains a high-efficacy treatment and patient adherence facilitator. However, its future growth may be tempered by internal competition from newer two-drug regimens like Dovato and Juluca, with evolving preferences for drugs with improved tolerability or safety profiles. The core patent for Triumeq is set to expire in April 2028, opening the door to generics. Sales of the drug were down 11% compared to 2023. Nevertheless, Triumeq is likely to sustain modest growth in 2025, buoyed by ongoing adoption in treatment-naïve and experienced patients, particularly in regions where it remains the standard of care. Nonetheless, growth may slow as newer regimens gain traction and as generics edge nearer post-patent expiry.

16. Epclusa (sofosbuvir/velpatasvir)

Indication(s): Chronic hepatitis C virus (HCV) infection

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $1.60 billion

2025 Outlook: After peaking at over $3 billion in earlier years, Epclusa’s revenue plateaued due to increased treatment saturation and a declining pool of untreated HCV patients in key markets. While details aren’t available on Epclusa’s sales, Gilead’s liver disease portfolio sales increased by 4% to $719 million in the fourth quarter compared to the same period in 2023, according to Gilead. Forecasts indicate a downward trajectory in mature markets post-2025 as generic alternatives enter the landscape. Despite this, demand may remain resilient in parts of the world with lower treatment penetration, ongoing diagnosis rates and emerging applications (e.g., treatment of patients with advanced liver disease or pediatric populations). Gilead’s separate subsidiary, Asegua Therapeutics, sells an authorized generic version of Epclusa.

17. NexGard (afoxolaner)

Indication(s): Flea and tick preventive and treatment for dogs

Manufacturer(s): Merial Animal Health, now part of Boehringer Ingelheim’s animal health division

2024 Sales (USD): $1.53 billion

2025 Outlook: NexGard continues to benefit from strong demand in the growing flea and tick preventive products market. The global flea and tick product market is forecasted to grow significantly, from ~$8.04 billion in 2024 to over $14.4 billion by 2032 (CAGR ~7.56%), driven by rising pet ownership, climate change and increased awareness of zoonotic risks. Boehringer’s net sales rose by about 4.65% year-on-year to €26.8 billion ($31.57 billion USD) in 2024 from €25.61 billion ($30.16 billion USD) in 2023, driven by ongoing high demand for the Jardiance product family and Ofev in its human pharma division, and NexGard in animal health. North America remains the largest regional market for isoxazoline-based drugs (which include afoxolaner). Boehringer Ingelheim reports robust performance in its parasiticide portfolio, noting that NexGard grew by 7.9% in the first half of 2025. NexGard is expected to sustain moderate, steady growth in 2025.

18. Mavyret (glecaprevir/pibrentasvir)

Indication(s): Acute and chronic hepatitis C virus (HCV)

Manufacturer(s): AbbVie

2024 Sales (USD): $1.31 billion

2025 Outlook: Mavyret’s $1.31 billion in 2024 sales is an 8.32% decline from 2023’s $1.43 billion revenue. Mavyret is facing revenue pressure due to its broad adoption over prior years, leading to a saturated patient pool in many mature markets. As one of the leading HCV regimens, Mavyret continues to play a central role in treating diagnosed but untreated HCV cases, especially given its eight-week approval for acute HCV. The global HCV treatment market is forecasted to grow from roughly $7.1 billion in 2024 to between $10.4 billion and $10.6 billion by mid-2030s, driven by screening efforts and expanding access in emerging markets. Mavyret is expected to deliver moderate, flat to slightly declining performance in key markets, given ongoing curative volumes and competition. However, it may retain stable demand in emerging or underdiagnosed markets, supported by its efficacy and label expansion into acute HCV treatment.

19. Odefsey (emtricitabine/rilpivirine/tenofovir alafenamide)

Indication(s): HIV

Manufacturer(s): Gilead Sciences

2024 Sales (USD): $1.29 billion

2025 Outlook: Odefsey came in as Gilead’s fourth best-selling HIV drug in 2024 with $1.29 billion in sales, slightly down from 2023’s $1.35 billion in total sales. Odefsey is a fixed-dose co-formulation of three anti-HIV drugs: tenofovir alafenamide (TAF), emtricitabine (FTC) and rilpivirine. Emtricitabine and tenofovir alafenamide are from Gilead Sciences, and rilpivirine is from Janssen Sciences Ireland UC. Odefsey’s earliest estimated generic entry isn’t expected until February 15, 2033. This long patent roadblock reduces short-term generic competition risks and supports ongoing exclusivity. In September 2022, Gilead reached an agreement with several generic drugmakers to resolve patent disputes. For 2025, HIV sales continued to expand, with a 7% increase in Q2 alone, driven by demand and pricing. Changes to Medicare’s prescription drug coverage are expected to reduce HIV medication revenues by roughly $900 million to $1.1 billion in 2025. This headwind might indirectly limit Odefsey’s growth, despite its patent moat.

20. Edurant (rilpivirine)

Indication(s): HIV

Manufacturer(s): Janssen

2024 Sales (USD): $1.27 billion

2025 Outlook: Edurant is expected to face increasing competition from newer, more convenient HIV regimens, particularly two-drug therapies such as ViiV’s Dovato and Juluca. Generic versions of Edurant could enter the US market as early as October 21, 2025, potentially accelerating price pressures. With patent protection waning and prescribing shifting toward newer combinations, Edurant may see moderate to sharp revenue declines. However, ongoing use in specific patient subgroups (e.g., lead-in with Cabenuva, certain pediatric cohorts) may help sustain some demand offset. The non-nucleoside reverse transcriptase inhibitor (NNRTI) is used in combination with other antiretroviral agents to treat HIV-1 infection in treatment-naïve adults and children two years of age and older. It is also used in combination with cabotegravir as a lead-in therapy in select, virologically suppressed patients aged 12 and above.