World health organization regional office for the western pacific regional guidelines

Considering rubella vaccine for the NIP

Guidelines on adding a new vaccine have been prepared by WPRO.¹⁰ A draft set of indicators of a country’s capacity to add a new vaccine is being developed by WPRO (see Annex 5).

As countries move towards measles elimination, the decision-making for rubella immunization needs to be reframed. Measles elimination provides the opportunity, at little extra cost, to also eliminate rubella. Furthermore, as it is recommended to have a wide-age range immunization campaign to introduce rubella vaccine, this campaign can have substantial benefits for measles control.

A key question in deciding about adding a new vaccine is comparing the costs and benefits from investing in the new vaccine compared with other available health investments. Because the full burden of rubella can be hard to estimate in some countries, Annex 5 provides a rough economic justification that is likely to apply to most settings.

For both measles and rubella elimination, over 95% immunity must be maintained for all cohorts in all districts. Lower levels of coverage can still provide reasonable control, but there will eventually be outbreaks. As measles is more infectious than rubella, the immunization efforts to eliminate measles should be more than adequate to eliminate rubella. Thus, adding rubella elimination to a country’s measles elimination initiative does not pose additional logistic challenges.

Rubella elimination can be easily added to a country’s measles elimination programme, and all countries moving towards measles elimination should consider adding rubella, as long as they meet the criteria of high coverage and sustainable funding.

Adding rubella vaccine

Issues for adding rubella vaccine

Although replacing measles with MR vaccine is simple, there are important considerations:

1. 
   The risk of increasing the number of CRS cases if high coverage cannot be achieved: coverage must be greater than the pre-vaccine era percentage of adults who are immune for the programme to be worthwhile.
   
2. 
   The extra cost of vaccine, and its relative priority in limited health budgets.
   
3. 
   The potential to create cohorts of susceptibles among those born before the introduction of rubella immunization.
   

Ensuring high coverage

Rubella is less infectious than measles. For countries that are moving towards measles elimination, rubella can be eliminated at lower levels of coverage (as it is less infectious). Therefore, this should not be an issue for countries that have adopted measles elimination. It becomes a political and financial decision to add rubella to the measles elimination programme.

Countries will require at least 95% coverage for measles elimination; therefore rubella can be safely introduced in countries that are committed to measles elimination.

Cost

Economic analyses have shown that rubella immunization is very cost-effective in both industrialised and developing countries.¹¹ The costs and impacts of a single case of CRS can be very high compared to the cost of the vaccine. In addition for Pacific people who frequently move to Australia, New Zealand, and the USA, the costs to the health and disability sectors of those countries create incentives for sub-regional control of rubella.

Although rubella immunization is cost-effective, and even potentially cost saving, additional funds are still needed (either internal or external) to enable its addition. The ongoing costs will be about US$1 for every newborn child. [Assumptions: two doses of MR given; additional cost is US$0.36 per dose (based on 2003 UNICEF costs for the 10-dose vial, above); and 40% wastage.]

As the cost to fully immunize a child in developing countries is estimated to be between US$15 to 30, the addition of rubella will only increase the overall immunization costs by 3 to 7%. In many countries, reducing the level of vaccine wastage of all EPI vaccines could generate sufficient savings to cover most or all of the cost of MR vaccine. [refer to Vaccine Security plan on reducing wastage]

There should be no operational implications or costs for the change from measles to MR, as it is simply a substitution of one 10-dose vial with another one that is identical – except for addition of rubella vaccine. There may be an increase in uptake as a result of the addition, which would increase costs, but would have correspondingly greater benefits.

Adding rubella vaccine is likely to be very cost effective, and will cost US$1.00 per newborn child for the routine programme (for two doses of MR).

Impact on older cohorts

Children born before the introduction of rubella immunization are more likely to enter adulthood susceptible to rubella, thus potentially increasing the risk of CRS (They are less likely to get infected as children because of the impact of immunization in preventing spread of the virus, but will not have protection from immunization). Therefore, at the same time (or before) routine rubella immunization is added, it is necessary to either:

1. 
   deliver a mass immunization campaign to all children aged 1 to 14 years (or even older); or
   
2. 
   protect all childbearing age women (CBAW) through immunization of girls at school, a mass immunization campaign, and/or post-partum.
   

A campaign has the advantage of having immediate effects in preventing the circulation of rubella virus; possibly eliminating the virus and creating sufficient population immunity to prevent re-establishment from any imported case. It will also be beneficial for measles control.

In most countries many adults remain susceptible to rubella. Therefore, the campaign would ideally be extended to include young adults. However, adults will require considerably more resources to reach. Therefore, a careful decision will be needed on the upper age range of the campaign based both on affordability and any data on the age-profile of susceptibility to rubella.

The danger of selective immunization of women, whether as school children or as CBAW, is that large numbers of people, including all males, may be still susceptible. Experience has shown that these susceptible groups have then suffered outbreaks with spread to pregnant women. Thus, if a campaign is feasible for adults, it is best to immunize both men and women.

If it is not feasible to deliver a campaign to protect these women a strategy of immunizing women after their first child can be a useful addition if it is known that CBAW remain unprotected.

A mass immunization campaign for all aged 1 to 14 years (or older) is recommended when introducing rubella vaccine so as to prevent ongoing infection, including epidemics, among older children and young adults.

The campaign’s upper age range depends on affordability; data on susceptibility; and the need to achieve very high coverage (>95%) in all of the targeted cohorts.

Protection of pregnant women is an adjunct control strategy that may be needed if the campaign does not protect most susceptible women.