Monitoring of coverage

Monitoring of vaccination coverage of pregnant women should be an integral part of the antenatal care and immunization monitoring mechanism.

Monitoring activities can include:

• Use of centralized nominal records, if available, to monitor coverage [39];
• Routine reviews of immunization registries and aggregation and reporting practices, including vaccination status of the mother recorded on the vaccination card of the infant if possible;
• Review of antenatal records to ensure influenza vaccination is included in the antenatal care register, antenatal care card and vaccination card tally sheets (routine reports from health or antenatal care centres can provide relevant information about immunization coverage; careful assessment is required due to the risk of reporting from multiple sources);
• Immunization coverage surveys such as DHS or MICS about vaccines received during pregnancy that systematically interview women who were pregnant for the past 12 months or that target women who were pregnant during the period of influenza vaccine administration.

Vaccination coverage strategies should be reported by all countries using the denominator of live births. Additional manipulations of the denominator can be used to check programmatic performance or determine in-country statistics. Depending on the vaccination strategy, countries may wish to modify the denominator they use to calculate vaccination coverage:

• In temperate countries with seasonal influenza epidemics, an annual campaign before the start of the transmission season will capture only those women who identify as pregnant and attend antenatal care during the 3–4-month period during which the vaccine is provided to protect against circulating influenza. Therefore, influenza vaccine coverage will not exceed 50% if the denominator used is all pregnant women in a year. In order to monitor effectively the proportion of eligible pregnant women who are vaccinated, system performance should be measured using the number of pregnant women attending antenatal care during the campaign period or the estimated pregnant population during the campaign period (estimated from monthly health facility denominators for maternal tetanus vaccination or antenatal care attendance).
• In tropical countries with moderate transmission throughout the year or multiple seasonal peaks, influenza vaccines can be distributed through routine delivery throughout the year or in biannual campaigns. For vaccine delivered throughout the year, the annual health facility denominators for maternal tetanus vaccination or antenatal care attendance could be retained. For biannual campaigns, either this denominator or the denominators identified for annual campaigns above could be applied to the number of months during which influenza vaccine is available in the year. For example, if two campaigns were conducted of 3-months duration, each vaccine would be available for 6 months of the year and the number of pregnant women attending care during those 6 months (or half the annual maternal tetanus/antenatal care attendance denominator) would be an appropriate denominator to measure vaccine coverage.

For countries in the Americas, an estimation method to calculate the denominator has been developed in the Regional Maternal and neonatal immunization regional field guide (see Toolbox). The guide suggests establishing the denominator on the basis of the live birth cohort for a given year. Here are proposed indicators for vaccination of pregnant women.