MATERIAL AND METHODS

A cross-sectional survey was applied in the months of February to May 2020 to medical interns, graduated physicians, residents, and specialists of the Fundación Oftalmológica de Santander (FOSCAL) in Floridablanca (Colombia).

The survey design was carried out in the Google forms program, including 20 questions with closed dichotomous and multiple-choice answers. The questionnaire included questions about academic training, year of graduation, general knowledge of the HZ vaccine (types and commercial names of the vaccine, age of indication); status of vaccination against HZ; attitude of physicians about the recommendation of vaccination for adult patients (older than 50 and older than 60 years of age); attitude about the importance and indication of the HZ vaccine at these ages; and knowledge about population at risk of HZ.

The sample was selected at convenience among physicians with direct employment ties, by providing services (in private clinics) or with academic ties with FOSCAL, for a total of 141 participants. A reminder message of the completion of the survey was sent by email every three weeks, for two times.

The subjects consented to participate in the survey, before proceeding to fill it out. The information obtained from the survey was protected by anonymity, since no identification data was required and sensitive data was not asked. Completion of the survey was voluntary, without financial compensation or any other type of incentive.

The health professionals were classified into four groups according to the level of training: a first group described by the acronym I&GP (Interns and General Practitioners); a second group made up of residents of different specialties; a third group including physicians with specialty (specialists), and the last group included physicians who also had subspecialty or fellowship, described by the acronym F&S (Fellows and Subspecialists). Questions that were unanswered were reported as "not responding".

For statistical analysis, Cronbach's alpha coefficient was estimated to establish the internal consistency of the survey. The response rate of the respondents was calculated and the responses were grouped according to the level of academic training of the respondents. A descriptive analysis was carried out with absolute and relative frequencies. Fisher's exact test was used to establish a relationship between the level of academic training and the answers obtained. An alpha of 0.05 was taken as the significance value. The R program was used for statistical analysis.

All procedures in this study were performed in accordance with the ethical standards of the institutional ethics committee Fundación Oftalmológica de Santander FOSCAL, and with the 1964 Helsinki declaration and its later amendments.

RESULTS

From the total 141 surveys sent, the percentage of response was 72.3 % with 102 answered surveys. 13.7 % of those surveyed reported that they had obtained a medical degree before 1985, 11 % between 1985 and 1995, 11.8 % between 1996 and 2005, 38.2 % between 2006 and 2015, and 14.7 % in 2016 or later. 9.8 % were interns in their last medical school year. The characteristics of the four groups of surveyed physicians are described in Table 1.

The internal consistency of the survey composed of 20 items, was high, since Cronbach's alpha coefficient yielded a value of 0.85.

DISCUSSION

The option of vaccination against HZ with a live attenuated virus vaccine (Zostavax, Merck Sharp & Dohme Limited, Hertfordshire, United Kingdom) has existed for approximately twelve years, but the use of this vaccine, even in developed countries, has been less than expected ⁸.

In our study in Colombia, 102 surveys were answered, and it was observed that there was no relationship between the knowledge about the existence of the HZ vaccine and the four groups of physicians, divided according to the level of medical training (P = 0.05). Knowledge on the existence vaccine was higher in the residents, followed by the F&S, specialists and I&GP groups, in descending order, but differences did not reach statistical significance. (Table 2). However, this trend may suggest that it is important to reinforce HZ vaccine education among undergraduate students in medical schools.

Surveys similar to the one applied in the present study have been carried out in other countries. In an article published by Tsui etal. in 2018, 138 physicians were surveyed at a United States institution (New York University Langone Health, NYULH). The authors found that they had a good knowledge of the recommendations of the Advisory Committee on Immunization Practices (ACIP) and the approval of the US FDA of vaccination against HZ in patients older than 60 years, reaching an average of 78% of correct answers to this question.

Comparatively, in the present study in Colombia, 70.6 % of those surveyed knew that it was indicated in those over 60 years of age. Of the physicians surveyed in the USA, 63 % knew that the indication had already been extended to those over 50 years of age, and similarly in our study this percentage was 60.8 %. In the present study, 52 % of those surveyed agreed that vaccination in those over 60 years of age was an important clinical priority, while in the North American study, this percentage was 35 % (8). Additionally, 56.9 % of those surveyed in the present study consider vaccination in people over 50 years of age an important clinical priority, which is the current recommendation of the American Academy of Ophthalmology (AAO), American Association of Dermatology (AAD) and Administration of US Food and Drug Administration (FDA). However, the clinical attitude contrasted with the medical knowledge found in the present survey among physicians in Colombia, since 41.2 % reported that they did not recommend the application of the vaccine to any of their patients over 50 years of age, and only the 5.9 % recommended it to more than 75 % of them (Table 3). Additionally, at the institution, only 5 % of the doctors over 50 years of age, who participated in the survey, had been immunized against HZ. The data also suggested a very low vaccination rate in the population attended by the surveyed physicians. Similarly, in the study by Tsui et al. ⁸ respondents considered that only 11 % of their immunocompetent patients aged 50 to 59 years had received the HZ vaccine, also reflecting a low vaccination rate in a North American institution.

Without a doubt, HZ is a condition that causes significant morbidity, and can leave important sequelae, such as postherpetic neuralgia, and visual consequences when it affects the eye (2-4). Additionally, in a large population cohort (more than 500,000 people in Korea), HZ significantly increased the risk of stroke and myocardial infarction even after meticulously correcting for potential confounders, especially in those relatively young who have less risk for atherosclerosis ¹³. In this regard, in our group of surveyed physicians, only 18.6 % reported knowing that suffering from HZ increased the risk of Cerebrovascular Disease (CVD).

In October 2017, the FDA approved a new recombinant vaccine, the varicella-zoster virus glycoprotein E subunit with adjuvant AS01B (Shingrix, GlaxoSmithKline, GSK, Research Triangle Park, North Carolina, USA) for prevention of HZ in adults aged 50 years and older and the ACIP recommended its use in immunocompetent adults aged 50 years or older ¹⁴. The efficacy of this new vaccine has been shown to be even higher than the previously available live attenuated virus vaccine, reaching figures of up to 97.4 % and 91.3 % in adults 50 years of age and older and 70 years of age and older, respectively ^{(12, 14)} while the live attenuated virus vaccine (Zostavax) achieved around 55 % effectiveness in protection ¹⁴. Based on the aforementioned percentages of efficacy with the Shingrix vaccine, the goal of achieving a substantial reduction in new cases of HZ seems very possible. However, to get there, we have a long way to go in Colombia. An obvious proof is that among the surveyed health professionals over 50 years of age, only a tiny minority (5 %) reported being already vaccinated. It is then necessary to work on a change in attitude, starting from this point. Health policies should be developed to in-crease the knowledge of professionals about the incidence, associated risks and prevention of HZ, emphasizing the groups of professionals where less knowledge of vaccination against HZ was found. Also, reinforcing a transfer of this knowledge to real-life clinical practice, since we found that despite having the knowledge, the surveyed physicians do not make recommendations on vaccination to their patients. Study of health costs, economic production of the patient and the negative effects on the quality of life of patients, published in other countries have shown the benefit of vaccination against HZ ^15,16.

We consider that our study contributes to identify the gaps in knowledge, and the critical points where work is required to cause a change in attitude and the practice of medicine and guide the activities to be carried out within the medical community. The knowledge and attitude of the physicians about HZ vaccine most probably play a role in the objective of increasing coverage of the HZ vaccine and eventually reducing the incidence and costs in health and quality of life associated with this disease.