1. Introduction
Vaccination is considered one of the most important measures of
preventing and controlling both human and animal diseases. The success
of every vaccination campaign is based on the vaccine characteristics
such as its efficacy and safety and on vaccination coverage and
compliance, which depend on human behaviour. The social-psychological
factors influencing vaccination compliance have been widely studied,
both in human medicine (e.g., Brewer et al.,
2017; Chapman & Coups, 1999;
Ratnapradipa et al., 2017; Schmid
et al., 2017 & Wheelock et al., 2013) and animal medicine (e.g., Elbres
et al., 2010; Eschle et al., 2020 & Gehrig et al., 2019). However, to
our knowledge, investigation of the change of vaccination compliance
through time (compliance dynamics) and the factors influencing it was
never published. Such information is of primary importance, first for
policymakers who wish to decide if vaccination against a certain disease
should be mandatory or voluntary. Second, these data are essential for
planning better intervention programs to prevent deterioration of
vaccination compliance.
To provide this information, we investigated the dynamics of Israeli
dairy farmers’ vaccination compliance against Lumpy Skin Disease (LSD),
a vector-borne viral disease. We chose LSD as it is considered one of
the most significant diseases affecting cattle. LSD is caused by the
lumpy skin disease virus (LSDV), a member of the Poxviridae family and
the genus Capripoxvirus
(Tuppurainen & Oura, 2012). The
disease is mostly characterized by the occurrence of localized or
generalized skin nodules. It is often accompanied by lethargy, reduced
appetite, edema, reduction in milk production, and might even cause
death (Tuppurainen & Oura, 2012). Until 2012, LSD was mainly limited to
Africa with some sporadic incursions which caused epidemics in the
Middle-East. From 2012, the disease had spread to Israel, Turkey,
Greece, Bulgaria and other Balkan countries, Armenia, Azerbaijan,
Kazakhstan, Georgia, the Russian Federation, China, India, Bangladesh,
Syria, Cambodia, Hong-Kong, Malaysia, Vietnam, and Thailand (EFSA, 2017;
EFSA, 2019 & OIE website).
The effectiveness of the Neethling vaccine used in Israel against LSD
was demonstrated beyond any doubt
(Ben-Gera et al.,
2015 & Klement et al., 2018). But
the vaccination strategy, determined by the policymakers, varied. Five
LSD epidemics occurred in Israel. The largest occurred in 2012 and
lasted until August 2013. Thereafter, compulsory vaccination was
implemented by the Israeli Veterinary Services (IVS). In June 2016, the
IVS changed its policy and vaccination against LSD became voluntary. In
2019, a new epidemic of LSD occurred in Israel. These events allowed us
to explore the dynamics of voluntary vaccination compliance among
Israeli farmers and their relation to the occurrence of LSD.
For this purpose, we followed the annual vaccination compliance between
2016-2019 among a cohort of 566 Israeli dairy farmers insured by
‘Hachaklait’ (a veterinary cooperation, owned by the farmers, which
provides veterinary services to about 80% of the dairy farms in
Israel). In addition, we investigated the demographic and
social-psychological factors influencing vaccination compliance among 90
dairy farmers using predefined questionnaires based on the theory of
planned behaviour (TPB), a reasoned action approach. Theories of
reasoned action and planned behaviour are widely used in the study of
medical behaviours (Albarracin et al., 2001; McEachan et al., 2016 &
Sok et al., 2021), including the motivation to vaccinate (Jozkowski &
Geshnizjani, 2016 & Sok et al., 2015).
The TPB predicts that a given future behaviour is explained by the
intention to perform it. The intention is directly explained by three
main constructs: attitude (A) (the person’s favourable or unfavourable
evaluation of the behaviour), subjective norms (SN) (the social
pressures a person perceives to perform or not the behaviour) and
perceived behavioural control (PBC) (the perceived own capability to
perform that behaviour) (Ajzen, 1985). Further on, Fishbein and Ajzen
developed the conceptualization of the TPB’s predictors of intention and
defined two distinguishable subdimensions to the existing unitary
definition of attitude (instrumental, experiential) and perceived
behavioural control (autonomy, capacity). Regarding the subjective
norms, a distinction between injunctive and descriptive aspects was made
(Fishbein & Ajzen, 2009). Injunctive norms refer to people’s
perceptions of what others would like them to do or what is expected of
them. Descriptive norms refer to people’s perceptions of what important
others do.
The results of this study point to the major factors that influence both
vaccination compliance and compliance deterioration. This reflects on
the potential effectiveness of strategies to increase vaccination
compliance.