Duck Viral Hepatitis Vaccination: Managing Maternal Antibody Interference and Field Efficacy

Vaccination is a key strategy for controlling Duck Viral Hepatitis (DVH), particularly in intensive duck production systems. It aims to reduce mortality in susceptible age groups, limit clinical infections and improve flock-level immunity^[1]. However, protection depends not only on vaccine selection but also on maternal antibody levels, vaccination timing and field implementation. 

Maternal Antibodies: Early Protection with a Limited Window^[1],[2] 

Inactivated DHAV vaccines are commonly administered to breeder ducks to support the transfer of maternal antibodies through egg yolk to their offspring. These antibodies provide initial protection while the ducklings' adaptive immune system is developing. 

The protection is temporary. Maternal antibody levels gradually decline during the first few weeks of life, potentially leaving ducklings vulnerable before active immunity is fully established. This creates a challenge when planning vaccination schedules. 

High maternal antibody titres can neutralise vaccine antigens and reduce the active immune response in young ducklings. Vaccinating too early may therefore limit vaccine-induced protection. Timing needs to account for the decline of maternally derived antibodies to achieve an effective immune response. 

Planning Vaccination Beyond the Breeder Level^[1],[3] 

DVH vaccination programmes generally begin with breeder immunisation to support maternal antibody transfer. In endemic or high-risk environments, a follow-up vaccination approach for ducklings may also be required. 

The need for follow-up vaccination depends on the duration of maternal protection and the risk of exposure. Since maternal antibodies do not provide lasting immunity, vaccination schedules should consider the period when passive protection declines and susceptibility increases. 

Vaccine Selection and Emerging Challenges^[1] 

Inactivated vaccines remain the most commonly used platform. Other approaches include attenuated vaccines, recombinant viral vectors, subunit vaccines, DNA-based vaccines and mRNA technologies. 

However, genetic diversification of DHAV, particularly among DHAV-1 and DHAV-3 lineages, raises concerns about genotype–vaccine mismatch. Antigenic differences between vaccine and circulating field strains may reduce protection, making molecular surveillance and periodic evaluation of vaccine strain selection important. 

Why Field Efficacy May Vary 

Even an appropriately selected vaccine may not deliver the expected protection if implementation is inconsistent. Vaccine quality, cold-chain maintenance, administration technique and the health condition of ducks at immunisation can influence vaccination success (Kim et al., 2024). Errors in these areas may result in inadequate immune responses and increase the risk of field infection. 

Clinical Takeaway 

Effective DVH vaccination requires coordination between breeder immunisation and appropriately timed duckling vaccination. Maternal antibody interference, changing DHAV variants and field-level implementation all influence protection. Regular monitoring of vaccination practices and molecular surveillance can help identify gaps and support timely adjustments to control programmes.

References:

1. Nuradji H, Khairullah AR, Dharmayanti NL, Wiyono A, Noor SM, Saepulloh M, Adji RS, Ekawasti F, Fauziah I, Prihandani SS, Nurjanah D. Duck hepatitis A virus (DHAV): Pathogenesis, diagnosis, prevention, and control in duck production systems. Open Veterinary Journal. 2026 Sep 1;16(9):5905. https://www.researchgate.net/profile/Sutiastuti-Wahyuwardani-4/publication/413903277
2. Wang Y, Guo Y, Wang H, Wu Z, Hong W, Sun H, Zhu S. Protection of ducklings from duck hepatitis a virus infection with ELPylated duck Interferon-α. Viruses. 2022 Mar 18;14(3):633. https://www.mdpi.com/1999-4915/14/3/633
3. Chen L, Zhang Q, Sun W, Mauk MG, Li Q. Detection method for identifying duck hepatitis A virus 3 virulent and attenuated strains based on RPA CRISPR single-base recognition system. Poultry science. 2025 Aug 1;104(8):105241. https://www.sciencedirect.com/science/article/pii/S0032579125004833