# Helminthic Infections and Vaccine Efficacy in Cattle: Implications for Disease Control and Sustainable Livestock Production

## TL;DR

This paper reviews how parasitic worm infections in cattle reduce vaccine effectiveness and suggests strategies to improve disease control and livestock sustainability.

## Contribution

The paper provides insights into how helminth infections alter immune responses to vaccines in cattle and proposes integrated management solutions.

## Key findings

- Chronic helminth infections like Fasciola hepatica and Ostertagia ostertagi suppress vaccine-induced immunity in cattle.
- Integrated strategies combining deworming, vaccination, and farm management can enhance herd protection and reduce anthelmintic use.

## Abstract

Livestock vaccines are essential for animal health and food production, yet their effectiveness can be reduced by common infections that alter how animals respond to immunization. Among these, parasitic worms such as Fasciola hepatica and Ostertagia ostertagi play a major role by changing the balance of the immune system, making it less able to develop strong and lasting protection after vaccination. This review describes how these parasites influence immune function in cattle and why infected animals often show weaker or delayed responses to vaccines. It also discusses practical strategies to reduce this problem, such as combining vaccination with timely parasite control, better diagnostic tools, and improved farm management. Understanding the interaction between infection and vaccination is vital to design more effective disease prevention programs and to improve animal welfare, productivity, and sustainability. These insights are especially important for farmers and veterinarians working in regions where parasitic infections are common and may help guide policies that enhance the global efficiency of livestock vaccination.

Vaccination remains a cornerstone of livestock disease control, yet its effectiveness under field conditions is often compromised by concurrent infections, particularly parasitic helminths. This review explores how infections shape vaccine-induced immunity in cattle, emphasizing the immunoregulatory mechanisms by which helminths interfere with protective responses. Chronic infections with Fasciola hepatica and Ostertagia ostertagi induce Th2-biased and regulatory immune environments that suppress antigen presentation, cytokine production, and memory formation and maintenance, leading to reduced vaccine efficacy. Evidence from experimental and field studies is scarce and constitutes a gap in our knowledge on how vaccines work in the field. Available data indicate that infection timing, intensity, and chronicity critically determine the extent of vaccine interference. The review highlights diagnostic approaches that can support targeted deworming before vaccination and proposes integrated management strategies combining parasite control, immunization, and nutritional optimization. Such approaches can mitigate helminth-driven immune suppression, enhance herd protection, and reduce dependence on anthelmintics. However, the impact of helminth infections on vaccine efficacy in cattle should be further assessed in the field. Understanding parasite–vaccine interactions is essential to refine vaccination programs, guide the development of next-generation vaccines, and promote sustainable livestock health in parasite-endemic areas.