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Quarterly surveillance report 1999 no. 1

Audit of a Hepatitis B Vaccination Program

Introduction

Hepatitis B virus (HBV) is a major public health problem worldwide. There are approximately 150 000 chronic carriers in Australia, and sequelae of infection account for 1200 deaths per year¹. Prevention is widely acknowledged to be the most effective approach to the problem^1,2. A vaccine has been available since 1982, and the standard immunisation schedule consists of three injections, at zero, one and six months³.

Most sexually transmitted disease (STD) clinics in Australia offer hepatitis B vaccination to groups at high risk of infection⁴. At Clinic 275, consenting new clients are screened for serological markers of HBV exposure. Free immunisation is offered to intravenous drug users (IDU), prostitutes, bisexual and homosexual men (MSM), Aborigines, Asians, regular sexual partners of the above, those with hepatitis C, and household contacts of hepatitis B carriers. Immunisation is also available by client request⁵.

Bhatti et al. note `when a policy to screen and immunise is in place, an exercise in audit... is an essential assessment of clinical performance’⁶, while Barlow identified uptake of the full course of hepatitis B vaccination as an issue worthy of review⁷. Such review is timely, given the decision of the NHMRC to strengthen their policy of targeted vaccination, in addition to expanding immunisation schedules to include vaccination of adolescents, supporting a WHO resolution to eliminate HBV infection⁸.

An audit was conducted to assess the Clinic 275 vaccination program. Delivery of vaccine is acknowledged as a proxy for outcomes such as reductions in morbidity and mortality⁹, so delivery served as the focus for this audit. The primary aims were to estimate the proportion of potentially susceptible patients completing immunisation at the clinic, examine the reasons for non-uptake of vaccination, and review the effectiveness of the reminder system. A secondary objective was to identify substantial differences in uptake and completion between the major sub-groups.

Methods

At Clinic 275, medical records are kept in a standardised format. Staff also maintain a manual register of HBV vaccinations. At the time of first vaccination, clients are given a card indicating the date of their second injection, and the due date of the third is filled in after the second has been given. The register is reviewed approximately once a month, and reminders are sent if the client is more than a fortnight overdue.

Section 1 – New clients eligible for vaccination.

The number of clients presenting for the first time between 1 January and 30 June 98, who reported male-to-male sex or IDU, was used as an estimate of high risk individuals offered vaccination. It was not possible to elicit data on all groups offered immunisation, but these target groups were thought to represent the greatest number eligible for vaccination.

Actual numbers of those undertaking vaccination between 1 January 98 and 27 April 99 were obtained from the ledger. Thus, the minimum period during which vaccination could be commenced, and be counted in this analysis, was ten months. Notes of eligible clients not commencing vaccination within this time were examined to determine the reasons for non-uptake.

Section Two – All clients commencing vaccination.

The second part of the audit was designed to determine the proportion completing the program, as well as supply information about groups of clients undergoing vaccination. Details of all clients having their first vaccination between 1 January and 30 June 98 were collected from ledger extracts, and supplemented by client notes. Results were combined to estimate the proportion of eligible individuals completing vaccination. Finally, the number of reminders was obtained from the ledger.

Results

Section One – New clients eligible for vaccination

Of 259 clients, MSM or IDU, presenting to the clinic for the first time between 1 January and 30 June 98, 79 (31%) had been vaccinated, or were immune as a result of past infection. Six of the former had started vaccination elsewhere and continued it at the clinic, while one received a booster.

In three of the remaining 180 cases it was inappropriate to offer vaccination at the time of presentation, and these were excluded from further consideration. Characteristics of the remaining 177 are summarised in Table 1. Thirteen had at least one other criterion for immunisation.

Table 1. Potentially eligible clients. Sex by risk group.

IDU = intravenous drug use(r)

MSM = men who have sex with men

Of those potentially susceptible clients, 48% undertook vaccination before 27 April 99 (Figure 1). However, 43% of IDU started vaccination, compared with 58% of MSM. One of four men categorised in both groups also commenced vaccination. Among females, 51% undertook vaccination, compared with 47% of men overall, and 38% of males reporting IDU. The difference in uptake between IDU and MSM achieved statistical significance (chi-square test, p<0.05), though that between male and female IDU did not.

Figure 1: Eligible new clients commencing vaccination within 10 to 16 months of registration

Total eligible
Commencing

IDU intravenous drug use(r)
MSM men who have sex with men

Of 92 who did not commence vaccination, 18 (20%) declined serology, and 22 (24%) did not return for results. Thirteen (14%) refused vaccination, while 12 (13%) said they would consider it, but did not return. Five (5%) intended to be vaccinated elsewhere. In 22 (24%) cases it was not recorded whether vaccination was offered.

Section Two – All clients commencing vaccination

During the period 1 January to 30 June 98, 184 patients undertook vaccination. Among these, 134 (73%) had at least two injections, and 69 (38%) completed the course. Forty four (24%) first presented to the clinic in 1996 or earlier. One client was excluded from consideration because she was not due for her third vaccination at the time of audit, as a result of being late for her second dose (Table 2, Figure 2).

* intravenous drug use(r)
# men who have sex with men
** regular partner of the above, or sex partner or household contact of HBV contact
## unclear why vaccination carried out; presumed to be patient request

Within 29 female IDU, 11 (38%) completed the series, compared to eight (20%) of 41 male IDU. MSM were significantly more likely to complete the series than IDU (p<0.02), but the difference between male and female IDU was not significant.

Figure 2: Number of doses received by clients commencing vaccination 1 January - 30 June 1998. Number by target group.

	One dose
	Two doses
	Completed

IDU intravenous drug use(r)
MSM men who have sex with men
A Aboriginal or Asian
C hepatitis C positive
S sex worker
RP regular partner of the above, or regular partner or household contact of HBV contact
U unclear why vaccination carried out; presumed to be patient request
M more than one risk category

Among clients presenting for second or third vaccinations, 143 presented without requiring a reminder letter. Reminders were sent to 135 clients, resulting in presentation of the client in 40 (30%) of instances. Thus, 51% of doses were administered without reminders, 14% of clients returned after receiving a letter, and in 34% of cases reminders were sent to no avail.

One reminder was not due at the time of audit, and 12 had not yet been sent (recently scheduled). In 17 cases, clients received their first injection elsewhere, so were not included in the reminder system, and in three cases the second dose was also administered elsewhere. Three clients left SA after their first injection and one after the second, these were excluded from the reminder system. In two instances clients received one dose but their vaccination was not recorded in the ledger, hence reminders were not sent. The remaining 44 doses are accounted for by third doses, due to be given, to patients who did not present for their second injection.

Estimates of the proportion of eligible individuals receiving one injection only, two only, and completing the series, are based on the assumption that uptake is the same across all target groups, compared with just IDU and MSM (Table 3). Completion rates by sex and target groups are shown in Figure 3.

Figure 3: Percentage of eligible clients receiving vaccination

IDU intravenous drug use(r)
MSM men who have sex with men

Discussion

Estimated delivery rates in this audit are not substantially different to those reported elsewhere. Uptakes of 48% overall, and 58% among MSM, compare favourably with a UK audit confined to homosexual and bisexual men¹⁰, where Bhatti et al found 42% (207/499) of those susceptible to infection undertook vaccination. However, they also reported that 68% of individuals completed the program within 16 months, a higher proportion than in the current study, where 38% overall, and 49% of MSM, completed the course. The difference may be partially due to the longer follow-up period in the UK study. Their estimated completion rate of 28% among all eligible patients is comparable with 29% for MSM here, and higher than the Clinic 275 rate of 18% for all eligible clients.

Most other reports are prospective studies rather than retrospective audits. One UK audit found similar completion rates among those who commenced the series to Bhatti et al¹¹. Two prospective studies in Canada reported compliance rates somewhat lower than those found at Clinic 275, 29% among all STD clients12 and 47% among MSM13. The reason for these differences is unclear. Self-addressed reminders were sent prior to the next dose in the UK audit. In one Canadian study the majority of defaulters were not contacted¹² while in the other¹³ more strenuous attempts were made to reach patients.

At Clinic 275, reminders increased return rates by 14%, demonstrating the usefulness of a recall system. One likely reason response rates were not higher is the mobile nature of the population served by the clinic.

In the above mentioned studies, numbers of IDU were insufficient to make comparisons between these and MSM, two groups identified by the Centers for Disease Control as among those at highest risk of infection14. A survey of clients at a Sydney STD clinic found 7% of IDU had been immunised compared with 28% of MSM¹⁵. At Clinic 275 an estimated 12% of eligible IDU completed vaccination, compared with 29% of MSM. These differences may reflect greater health seeking behaviour among MSM compared with IDU. Within the IDU there were higher uptake and completion rates among females, though the differences were not significant. Numbers within other groups were too small to make valid comparisons.

Limitations

The audit period was chosen to allow time for patients commencing vaccination at the end of the period to complete the program, with a margin of nearly four months. However, the assumption that this would be enough time was too optimistic, as injections were administered up to seven months after the due date. Clinical experience suggests some doses are given up to two years late, often opportunistically, when patients present for other reasons. Therefore the rates for completion and response to reminders are underestimates. Fortunately, delays in administration of later doses do not impair the immune response to the vaccine¹⁶. In addition, some clients may have been ineligible for vaccination, due to past infection, on the basis of serology results. It was not possible to estimate the number who commenced vaccination at the clinic and completed it elsewhere, or how many of those who indicated that they would undertake vaccination elsewhere actually did so.

It was surprising that about a quarter of the clients commencing vaccination in the first half of 1998 had presented to the clinic for the first time at least a year earlier, and up to ten years previously. While some would have commenced the high risk behaviour (such as IDU), after the first visit, others may have been vaccinated after consideration of an earlier offer, so the actual number eventually undertaking immunisation is probably higher than estimated. In retrospect, it may have been useful to choose an earlier period for the audit. However, a disadvantage would have been inaccurate reflection of current practices.

It was not determined whether uptake across all target groups is similar to that by MSM and IDU. However, given the relatively small proportions of other groups, even large variations would be unlikely to make a difference overall.

Recommendations

Several factors may contribute to poor immunisation rates, particularly the need for multiple doses at lengthy intervals. An accelerated program might lead to improved completion rates. Although such a schedule, with injections at zero, one, and two months, is approved, a booster dose at 12 months is required⁸. There are conflicting reports about whether it actually increases compliance^17,18,19 but it may be worth testing, particularly among IDU.

Lack of knowledge has been identified as a barrier to vaccination, and a recent survey found the reasons most frequently cited by MSM for not being immunised was lack of awareness of the vaccine, and the belief that the respondents were not at risk²⁰. There have been suggestions that with the emphasis on education about HIV/AIDS, the perceived importance of other STDs has declined^15,21. Behavioural changes in response to this education seem to have had an impact on the prevalence of HBV infection among MSM^15,22, though not IDU²². However, there is a higher prevalence of HBV and it is more infectious than HIV, so some activities considered safe in terms of HIV transmission have a relatively high chance of spreading HBV²¹. Increased education about hepatitis B should improve both uptake and completion of vaccination amongst people at high risk of infection. On an individual level, the clinic’s education pamphlet is a useful tool for reinforcing the benefits of vaccination.

In at least four cases in which no record of offer was made, the last occurrence of high risk activity (mainly IDU) was between two and ten years earlier. Because the vaccination policy specifies past as well as current IDU or male-to-male sex⁵, these cases were included in the audit. Realistically, the perception of risk, by both doctor and client in such cases, would have been lower than with current high-risk activity, which is the priority of the program²³. During 1998, the pertinent section of the casenotes was changed so information on such behaviour in the past 12 months is recorded, which enables easy identification of those most at risk. It is important that visiting staff and students are reminded of the need to offer vaccination and record its refusal or otherwise.

Finally, plans to semi-automate the reminder system in the near future should reduce the associated workload and facilitate prompt forwarding of letters.

Many other recommendations suggested in the literature are already in place at Clinic 275. These include a printed reminder of the screening and immunisation policy for clinicians¹⁰, patient-held cards documenting the schedule¹¹, free vaccination¹⁵, and administration of injections¹⁹.

Conclusion

While uptake rates are greater than some reported elsewhere, the figures presented here are underestimates. The low overall completion rate lends weight to the belief that universal vaccination will be more effective than targeting of high risk groups2, especially given that many measures for enhancing completion have already been implemented at Clinic 275. However, the selective strategy will be required for some years, while the cohorts of vaccinated children grow older.

The leading cause of failure to complete vaccination was lack of compliance with the dosing schedule, followed by the combination of refusal of blood tests and failure to attend for results. An accelerated schedule is worth considering, particularly for IDU. Emphasis on education regarding HBV, and the importance of immunisation, might improve uptake and completion rates. Finally, the recall system does improve compliance, and improved automation should ease the administrative burden of sending reminders.

References

1. Gust ID. Control of hepatitis B in Australia. MJA 1992; 156: 819-21.
2. Francis DP. The public’s health unprotected - reversing a decade of underutilization of hepatitis B vaccine. JAMA 1995; 272: 1242-1243.
3. Holmes KK, Mardh PA, Sparling PF, Wesner PJ (Eds.) Sexually Transmitted Diseases, 2nd Ed. New York, McGraw-Hill Inc., 1990.
4. Marks C, Tideman RL, Minel A. Evaluation of sexual health services within Australia and New Zealand. MJA 1997; 166: 348-352.
5. Clinic 275 Operations Manual, 1998.
6. Bhatti N, Gilson RJC, Beecham M, Williams P, Matthews MP, Tedder RS, Weller IVD. Audit in practice. Failure to deliver hepatitis B vaccine: confessions from a genitourinary medicine clinic. BMJ 1991; 303: 97-101, p. 100.
7. Barlow D. Medical audit and genitourinary medicine. Int J STD & AIDS 1993; 4: 125-127.
8. National Health and Medical Research Council Hepatitis B Working Party. Recommendations on Hepatitis B Immunisation. Canberra, Australian Government Publishing Service, 1996.
9. Hopkins A. Measuring the quality of medical care. London, Royal College of Physicians, 1990.
10. Bhatti N, Gilson RJC, Beecham M, et al. Failure to deliver hepatitis B vaccine: confessions from a genitourinary medicine clinic. BMJ 1991; 303: 97–101.
11. Stevenson M, El-Dalil A, Richmond R, Wade AAH. An audit of hepatitis B vaccination compliance rates in two genitourinary medicine clinics. Int J STD & AIDS 1995; 6: 364-365.
12. Sellors J, Zimic-Vincetic M, Howard M, Chernesky MA. Lack of compliance with hepatitis B vaccination among Canadian STD clinic patients: candidates for an accelerated immunization schedule? Can J Pub Health 97; 88: 210–211.
13. Yuan L, Robinson G. Hepatitis B vaccination and screening for markers at a sexually transmitted disease clinic for men. Can J Pub Health 1994; 85: 338-341.
14. Centers for Disease Control. Recommendations for protection against viral hepatitis. MMWR 1985; 34: 313–335.
15. Anderson B, Bodsworth NJ, Rohsheim RA, Donovan BJ. Hepatitis B virus infection and vaccination status of high risk people in Sydney: 1982 and 1991. MJA 1994; 161: 368-371.
16. National Health and Medical Research Council. The Australian Immunisation Handbook, 6th Ed. Australian Government Publishing Service, Canberra, 1997.
17. Weinstock HS, Bolan G, Moran JS, Peterman TA, Polish L, Reingold AL. Routine hepatitis B vaccination in a clinic for sexually transmitted diseases. Am J Pub Health 1995; 85: 846-849.
18. Asboe D, Rice P, de Ruiter A, Bingham JS. Hepatitis B vaccination schedules in genitourinary medicine clinics. Genitourin Med 1996; 72: 210–212.
19. Dal-Re R, Gonzalez A, Ramirez V, Ballesteros J, del Romero J, Bru F. Compliance with immunization against hepatitis B. A pragmatic study in sexually transmitted disease clinics. Vaccine 1995; 13: 163–167.
20. Neighbors K, Oraka C, Shih L, Lurie P. Awareness and utilization of the hepatitis B vaccine among young men in the Ann Arbor area who have sex with men. J Am Coll Health 1999; 47: 173–178.
21. Australasian College of Sexual Health Physicians, 1997. Gay men, hepatitis vaccination & HIV – a fact sheet for doctors.
22. Centers for Disease Control. Hepatitis B virus – a comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination. Recommendations of the Immunization Practices Advisory Committee. MMWR 1991; 40 (RR-13) 1–19.
23. Discussion with Clinic 275 manager, Dr Russell Waddell.

Kylie Fardell
Flinders University
May 1999

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