Media Briefing: Ticks and Lyme Disease

Why It Matters

Rising tick populations driven by climate change threaten public health and healthcare costs, making effective prevention, surveillance, and vaccine deployment critical for protecting millions of Americans.

Key Takeaways

• Tick populations rising sharply due to warming climate and land changes
• Emergency room visits for tick bites up 25% in April alone
• New Lyme vaccine shows 73‑75% efficacy but requires three doses plus boosters
• Personal protection: long pants, permethrin-treated clothing, thorough post‑outdoor checks
• Expanding lone‑star tick spreads alpha‑gal allergy further northward

Summary

The Johns Hopkins Bloomberg School of Public Health hosted a media briefing to examine the surge in tick‑borne diseases, focusing on Lyme disease, emerging pathogens, and vaccine development. Professors Nicole Baumgart and Thomas Hart highlighted that climate warming, altered land use, and shifting biodiversity—particularly the rise of the white‑footed mouse—are expanding tick habitats northward and into higher altitudes, driving record numbers of emergency‑room visits. Data presented showed a 25% increase in tick‑bite related ER visits in April compared with last year, and CDC estimates of roughly half a million Lyme cases annually. A phase‑three trial of a new Lyme vaccine demonstrated 73‑75% efficacy, yet its three‑dose schedule plus annual boosters may limit broad adoption. Meanwhile, the lone‑star tick, now the most common species collected in Maryland, is spreading alpha‑gal syndrome, and the Ixodes scapularis continues to transmit Powassan virus and other pathogens. Prof. Baumgart emphasized that current prevention relies on simple measures—hot showers, tick checks, long pants tucked into socks, light‑colored permethrin‑treated clothing, and creating tick‑free zones around homes. Prof. Hart added community strategies such as mulching forest edges, limiting rodent and deer access, and targeted pesticide applications. Both underscored ongoing research into diagnostics, treatments, and next‑generation vaccines. The briefing underscores an urgent need for coordinated public‑health action: scaling up preventive education, investing in vaccine rollout strategies, and integrating climate‑adaptation monitoring to curb the expanding tick season. Failure to act could exacerbate healthcare burdens, blood‑supply safety, and the prevalence of chronic post‑treatment Lyme symptoms.

Original Description

The Johns Hopkins Bloomberg School of Public Health hosted a media briefing on May 5, 2026, about ticks and the growing threat of Lyme and other tickborne diseases.

Cases of Lyme disease have been on the rise in the U.S., according to the CDC, mainly in the Northeast, Upper Midwest, and parts of the West – though ticks’ habitats are expanding due to climate change.

Emergency department visits for tick bites were up more than 25% in April 2026 over the previous April, according to the CDC, an early indication that we might be facing a challenging year ahead.

State health departments reported more than 89,000 cases of Lyme disease in humans to the CDC in 2023, the most recent year numbers were published. Research suggests, however, that the actual number of cases is likely closer to half a million, which points to significant problems with underreporting, especially in endemic areas and in areas where tickborne diseases seem rare due to misdiagnoses.

If left untreated, Lyme disease can lead to serious complications affecting the heart, joints, and nervous system. Other tickborne illnesses are also of concern, including Powassan virus and Heartland virus. There is currently no vaccine against tickborne illnesses, though new Lyme disease vaccines are in development, and one created by Valneva with Pfizer has just completed a Phase 3 human clinical trial.

Topics discussed:

Why tickborne illnesses are increasing

The symptoms and outcomes of the illnesses

How people can protect themselves

The latest research

Current status of vaccine development

Insights from:

Nicole Baumgarth, DVM, PhD, a Bloomberg Distinguished Professor of Immunology and Infectious Diseases in the Department of Molecular Microbiology and Immunology and director of the Lyme and Tickborne Diseases Research and Education Institute at the Johns Hopkins Bloomberg School of Public Health.

Thomas Hart, PhD, an infectious disease microbiologist at the Lyme and Tickborne Diseases Research and Education Institute and assistant professor in the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health.

0:00 Introduction

01:36 What is worrying about this tick season

05:25 Ticks are more prevalent this year

10:05 Post-treatment Lyme disease syndrome

12:00 Outlook for a vaccine

13:18 How El Nino might affect ticks

14:44 Other tickborne diseases

16:00 ER visits

16:26 How would climate change affect tick regions

17:26 How common are tickborne diseases in Africa

19:10 How brain is affected by tickborne diseases

20:04 Affect on farm workers

21:26 Treatment for the disease

23:04 Situation and diagnosis in the midwest

25:32 Why are misdiagnoses so common

26:54 Are there surprises this year

27:40 Doctor visits for tick bites

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