Progress towards elimination of measles in Kenya, 2003-2016

Less than one-fifth of Ethiopian children were vaccinated for measles second dose; evidence from the Ethiopian mini demographic and health survey 2019

Ethiopia introduced the measles second dose vaccine from the routine expanded immunization program in 2018. Shreds of evidence are scarce on the measles second dose vaccination coverage and its associated factors in Ethiopia. We aimed to assess the measles second dose vaccination coverage and associated factors in Ethiopia using the recent Ethiopian Mini Demographic and Health Survey (EMDHS) 2019 data. An in-depth secondary data analysis was conducted based on the Ethiopian mini demographic and health survey 2019 data; which was a cross-sectional survey targeted on key indicators of maternal and child health. A weighted sample of 965 children was included in the analysis. A multi-level mixed effect logistics regression model was fitted. Adjusted Odds Ratio (AOR) with 95 %CI was reported for statistically significant variables. The measles second dose coverage was 12.36 % (95 %CI = 10.89, 15.44). Not vaccinated for the third dose of pentavalent vaccine (Penta 3) (AOR = 0.60, 95 %CI: 0.37, 0.95), age of the child [13 to 23 months (AOR = 2.14, 95 %CI: 1.05, 4.36), 24 to 36 months (AOR = 2.58, 95 %CI: 1.32, 5.05)], household head educational status [no education (AOR = 0.51,95 %CI: 0.26, 0.99), primary (AOR = 0.44, 95 %CI: 0.23, 0.85)], and living in south nation, nationalities and peoples region (SNNPR) (AOR = 2.83,95 %CI: 1.12, 7.11) were significantly associated with measles second dose vaccination coverage. Measles second dose vaccination coverage was low in Ethiopia. Age of the child, being vaccinated for the Penta 3, educational status of the household head, and region of residence were significant determinants of measles second dose vaccination coverage.

Epidemiological characteristics of a protracted and widespread measles outbreak in the Democratic Republic of Congo, 2018 - 2020

Introduction

measles is a highly contagious viral disease. Since 2011, the Democratic Republic of Congo (DR Congo) has had the first dose measles vaccination coverage of less than 80% according to the World Health Organization - United Nations International Children's Emergency Fund (WHO-UNICEF) coverage estimates, and measles mass vaccination coverage of less than the required coverage level of 95% by survey. Starting in August 2018, the country experienced an increase in measles case reports which continued through to early 2020. Epidemiological aspects of the outbreak are described in this article.

Methods

we analysed aggregate weekly passive surveillance data from the DR Congo for the years 2018 - 2020 to understand the trends of occurrence of suspected measles cases. We also analysed the measles case-based surveillance database to understand the epidemiological characteristics of confirmed cases of measles and rubella during the same period of time.

Results

a total of 458,156 suspected measles cases and 8,127 deaths were reported between 1^st January 2018 and 31^st December 2020, with the majority of cases and deaths reported in 2019. Only 2.9% of these cases were reported through the case-based surveillance system, with 31,639 cases being confirmed as measles by the laboratory, by epidemiological linkage and on clinical compatibility. Children less than 5 years of age were most affected with a cumulative incidence of 960 cases per 1,000,000 inhabitants. Only 41% of the confirmed cases were vaccinated. Maindombe and Tshopo provinces had the highest cumulative incidence levels. There was a distinct geographic progression of the outbreak between provinces during the course of the three years. A total of 1760 lab confirmed rubella cases were confirmed in various provinces among the cases investigated with blood specimens, 93% of whom were less than 15 years of age.

Conclusion

the recent gaps in vaccination coverage, the age pattern of confirmed cases and the lack of vaccination history in the majority of cases is suggestive of failure to vaccinate as the likely cause of this large and protracted outbreak. Efforts to improve vaccination coverage and the measles surveillance system are needed in order to prevent the occurrence of future outbreaks and to avert measles-related deaths.

The sensitivity of acute flaccid paralysis surveillance - the case of South Sudan: retrospective secondary analysis of AFP surveillance data 2014-2019

INTRODUCTION

South Sudan has made quite impressive progress in interrupting wild poliovirus and maintaining a polio-free status since the last case was reported in 2009. South Sudan introduced different complementary strategies to enhance acute flaccid paralysis (AFP) surveillance. Hence, the objective of this study is to evaluate the sensitivity of the surveillance system using the WHO recommended surveillance standard and highlight the progress and challenges over the years.

METHODS

we conducted a retrospective, descriptive, quantitative study design and used the available secondary AFP surveillance database.

RESULTS

the overall non-polio AFP rate was 6.2/100,000 children under 15 years old in the study period. The stool adequacy was maintained well above the certification level of surveillance. The two main surveillance performance indicators were met at the national level throughout the study period. In contrast, only five out of ten states persistently attained and maintained the two main surveillance performance indicators throughout the study period, while in 2019 all states achieved except for Jonglei state. During the analysis period, no wild poliovirus was isolated except two circulating Vaccine Derived Poliovirus Type 2 (cVDPV2) cases in 2014 and one Immunodeficiency Vaccine Derived Poliovirus Type 2 (iVDPV2) case in 2015. However, on average, three cases were classified as polio compatible with each year of the study.

CONCLUSION

South Sudan met the two key surveillance performance indicators and had a sensitive AFP surveillance system during the period studied. We recommend intensifying surveillance activities in the former conflict-affected states and counties to maintain polio-free status.

Epidemiology of measles cases, vaccine effectiveness, and performance towards measles elimination in The Gambia

Introduction

In 2011, member states of the World Health Organization (WHO) Africa Regional Office (AFRO) resolved to eliminate Measles by 2020. Our study aims to assess The Gambia’s progress towards the set AFRO measles elimination target and highlight surveillance and immunisation gaps to better inform future measles prevention strategies.

Material and methods

A retrospective review of measles surveillance data for the period 2011–2019, was extracted from The Gambia case-based measles surveillance database. WHO—UNICEF national coverage estimates were used for estimating national level MCV coverage. Measles post campaign coverage survey coverage estimates were used to estimate national measles campaign coverage.

Results

One hundred and twenty-five of the 863 reported suspected cases were laboratory confirmed as measles cases. More than half (53.6%) of the confirmed cases have unknown vaccination status, 24% of cases were vaccinated, 52.8% of cases occurred among males, and 72.8% cases were among urban residents. The incidence of measles cases per million population was lowest (0) in 2011–2012 and highest in 2015 and 2016 (31 and 23 respectively). The indicator for surveillance sensitivity was met in all years except in 2016 and 2019. Children aged 5–9 years (Incidence Rate Ratio—IRR = 0.6) and residents of Central River region (IRR = 0.21) had lower measles risk whilst unvaccinated (Adjusted IRR = 5.95) and those with unknown vaccination status (IRR 2.21) had higher measles risk. Vaccine effectiveness was 89.5%.

Conclusion

The Gambia’s quest to attain measles elimination status by 2020 has registered significant success but it is unlikely that all target indicators will be met. Vaccination has been very effective in preventing cases. There is variation in measles risk by health region, and it will be important to take it into account when designing prevention and control strategies. The quality of case investigations should be improved to enhance the quality of surveillance for decision making.

Descriptive epidemiology of measles cases in Bauchi State, 2013-2018

BACKGROUND

Measles accounts for high morbidity and mortality in children, especially in developing countries. In 2017, about 11,190 measles cases were recorded in Nigeria, including Bauchi State. The aim of this study was to describe the trend and burden of measles in Bauchi State, Nigeria.

METHOD

We analyzed secondary data of measles cases extracted from the Measles Surveillance data system in Bauchi State from January 2013 to June 2018. The variables extracted included age, sex, doses of vaccination, case location and outcome. Data were analyzed using descriptive statistics, logistic regression, and multiplicative time series model (α = 0.05).

RESULTS

A total of 4935 suspected measles cases with an average annual incidence rate of 15.3 per 100,000 population and 57 deaths (Case Fatality Rate, CFR: 1.15%) were reported. Among the reported cases, 294 (6%;) were laboratory-confirmed, while clinically compatible and epi-linked cases were 402 (8%) and 3879 (70%), respectively. Of the 4935 measles cases, 2576 (52%) were males, 440 (9%) were under 1 year of age, and 3289 (67%) were between 1 and 4 years. The average annual incidence rate among the 1-4 year age-group was 70.3 per 100,000 population. The incidence rate was lowest in 2018 with 2.1 per 100,000 and highest in 2015 with 26.2 per 100,000 population. The measles cases variation index per quarter was highest in quarter 1 (198.86), followed by quarter 2 (62.21) and least in quarter 4 (10.37) of every year. Only 889 (18%) of the measles cases received at least one dose of measles vaccine, 2701 (54.7%) had no history of measles vaccination while 1346 (27.3%) had unknown vaccination status. The fatality of measles in Bauchi State were significantly associated with being under 5 years (AOR = 5.58; 95%CI: 2.19-14.22) and not having at least a dose of MCV (OR = 7.14; 95%CI: 3.70-14.29).

CONCLUSION

Measles burden remains high in Bauchi State despite a decrease in its incidence over the study years. Most of the cases occurred in the first quarter of every year. Improved routine measles surveillance for prompt case management could reduce the burden of the disease in Bauchi State.

Measles epidemiology and vaccination coverage in Oromia Region, Ethiopia: Evidence from surveillance, 2011-2018

Despite a reported high coverage of measles-containing vaccine (MCV), low-income countries including, Ethiopia, have sustained high measles transmission with frequent outbreaks. We investigated the distribution of measles infection and vaccination in Oromia Regional State, Ethiopia. According to the World Health Organization (WHO) and the Ethiopian measles case classification guidelines, measles cases were classified as laboratory-confirmed, clinically compatible, and epidemiologically linked. We derived measles vaccination coverage estimates using reported measles vaccine efficacy and, the proportion of measles cases vaccinated with measles vaccine at least once from the surveillance data. We calculated measles effective reproduction number (R_e) in the region. Almost twenty-five thousand measles cases were reported through the surveillance system, with more than 50% of the suspected and confirmed measles cases reported in 2015. Measles had sustained and high transmission rate with uneven distribution among the zones. Children between 1 and 4 years of age and MCV unvaccinated individuals were the most affected groups. In all the zones, the average surveillance-estimated MCV coverage among both infants and under-five children was significantly lower than the WHO recommended minimum 90% threshold herd-immunity. With this level of vaccination coverage, an infected case can transmit to more than four individuals. Nevertheless, the administrative coverage reports for the concurrent period were consistently above 90%. The estimated MCV coverage across the Oromia region was well below the recommended herd-immunity threshold. It partly explains the apparent mismatch of sustained measles transmission and outbreaks despite the very high administrative coverage estimates. Oromia regional health bureau, in collaboration with key stakeholders, should make a concerted effort to increase the effective-coverage of MCV to at least 90%. Additionally, multiple-dose MCV has to be scaled-up and accompanied with appropriate geographic and age targeting using evidence from surveillance data. Immediate programmatic action is needed to improve the quality of measles surveillance.

The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya

BACKGROUND

The COVID-19 pandemic has disrupted routine measles immunisation and supplementary immunisation activities (SIAs) in most countries including Kenya. We assessed the risk of measles outbreaks during the pandemic in Kenya as a case study for the African Region.

METHODS

Combining measles serological data, local contact patterns, and vaccination coverage into a cohort model, we predicted the age-adjusted population immunity in Kenya and estimated the probability of outbreaks when contact-reducing COVID-19 interventions are lifted. We considered various scenarios for reduced measles vaccination coverage from April 2020.

RESULTS

In February 2020, when a scheduled SIA was postponed, population immunity was close to the herd immunity threshold and the probability of a large outbreak was 34% (8-54). As the COVID-19 contact restrictions are nearly fully eased, from December 2020, the probability of a large measles outbreak will increase to 38% (19-54), 46% (30-59), and 54% (43-64) assuming a 15%, 50%, and 100% reduction in measles vaccination coverage. By December 2021, this risk increases further to 43% (25-56), 54% (43-63), and 67% (59-72) for the same coverage scenarios respectively. However, the increased risk of a measles outbreak following the lifting of all restrictions can be overcome by conducting a SIA with ≥ 95% coverage in under-fives.

CONCLUSION

While contact restrictions sufficient for SAR-CoV-2 control temporarily reduce measles transmissibility and the risk of an outbreak from a measles immunity gap, this risk rises rapidly once these restrictions are lifted. Implementing delayed SIAs will be critical for prevention of measles outbreaks given the roll-back of contact restrictions in Kenya.

Vaccination strategies for measles control and elimination: time to strengthen local initiatives

BACKGROUND

Through a combination of strong routine immunization (RI), strategic supplemental immunization activities (SIA) and robust surveillance, numerous countries have been able to approach or achieve measles elimination. The fragility of these achievements has been shown, however, by the resurgence of measles since 2016. We describe trends in routine measles vaccine coverage at national and district level, SIA performance and demographic changes in the three regions with the highest measles burden.

FINDINGS

WHO-UNICEF estimates of immunization coverage show that global coverage of the first dose of measles vaccine has stabilized at 85% from 2015 to 19. In 2000, 17 countries in the WHO African and Eastern Mediterranean regions had measles vaccine coverage below 50%, and although all increased coverage by 2019, at a median of 60%, it remained far below levels needed for elimination. Geospatial estimates show many low coverage districts across Africa and much of the Eastern Mediterranean and southeast Asian regions. A large proportion of children unvaccinated for MCV live in conflict-affected areas with remote rural areas and some urban areas also at risk. Countries with low RI coverage use SIAs frequently, yet the ideal timing and target age range for SIAs vary within countries, and the impact of SIAs has often been mitigated by delays or disruptions. SIAs have not been sufficient to achieve or sustain measles elimination in the countries with weakest routine systems. Demographic changes also affect measles transmission, and their variation between and within countries should be incorporated into strategic planning.

CONCLUSIONS

Rebuilding services after the COVID-19 pandemic provides a need and an opportunity to increase community engagement in planning and monitoring services. A broader suite of interventions is needed beyond SIAs. Improved methods for tracking coverage at the individual and community level are needed together with enhanced surveillance. Decision-making needs to be decentralized to develop locally-driven, sustainable strategies for measles control and elimination.

Economic value of vaccinating geographically hard-to-reach populations with measles vaccine: A modeling application in Kenya

BACKGROUND

Since special efforts are necessary to vaccinate people living far from fixed vaccination posts, decision makers are interested in knowing the economic value of such efforts.

METHODS

Using our immunization geospatial information system platform and a measles compartment model, we quantified the health and economic value of a 2-dose measles immunization outreach strategy for children <24 months of age in Kenya who are geographically hard-to-reach (i.e., those living outside a specified catchment radius from fixed vaccination posts, which served as a proxy for access to services).

FINDINGS

When geographically hard-to-reach children were not vaccinated, there were 1427 total measles cases from 2016 to 2020, resulting in $9.5 million ($3.1-$18.1 million) in direct medical costs and productivity losses and 7504 (3338-12,903) disability-adjusted life years (DALYs). The outreach strategy cost $76 ($23-$142)/DALY averted (compared to no outreach) when 25% of geographically hard-to-reach children received MCV1, $122 ($40-$226)/DALY averted when 50% received MCV1, and $274 ($123-$478)/DALY averted when 100% received MCV1.

CONCLUSION

Outreach vaccination among geographically hard-to-reach populations was highly cost-effective in a wide variety of scenarios, offering support for investment in an effective outreach vaccination strategy.