Haiti + 3 more

Epidemiological Update: Diphtheria (5 November 2021)

Format
Situation Report
Sources
Posted
Originally published
Origin
View original

Attachments

In the context of the COVID-19 pandemic, the Pan American Health Organization / World Health Organization (PAHO/WHO) reiterates to Member States that vaccination and epidemiological surveillance for vaccine-preventable diseases should be considered essential health services and should not be interrupted. Given the decline in diphtheria vaccine coverage, PAHO/WHO also reminds Member States that it is important to have a plan to vaccinate the most vulnerable populations and to maintain a permanent supply of diphtheria antitoxin to control potential outbreaks.

Situation Summary in the Americas

In 2021, between epidemiological week (EW) 1 and EW 42, four countries reported confirmed cases of diphtheria: Brazil with one case, Colombia with one fatal case, Haiti with 18 cases including 3 deaths, and the Dominican Republic with 18 cases including 12 deaths.

The Region of the Americas has reported a steady decline in vaccination coverage since 2010. Vaccination coverage for the third dose of diphtheria, tetanus, and pertussis (DTP3) vaccine in the Region of the Americas declined from 94% to 84% between 2010 and 2020. Between January 2019 and January 2020, DPT3 coverage decreased by 33%. The decline in coverage was observed in most countries in the Region, thereby increasing the population of individuals susceptible to vaccine-preventable diseases. Furthermore, the COVID-19 pandemic has also affected the epidemiological and laboratory surveillance systems for vaccine-preventable diseases.

The following is the epidemiological situation for diphtheria in Colombia, Haiti, and the Dominican Republic, countries that have reported new confirmed cases since the Epidemiological Update on Diphtheria published on 25 June 2021.

In Colombia, between EW 1 and EW 41 of 2021, 7 probable cases of diphtheria were reported, of which one was laboratory-confirmed, 5 were discarded, and one remains under investigation.

During EW 41 of 2021, a confirmed fatal case of diphtheria was reported in Sucre Department in a 10-year-old Venezuelan female who had resided in Santiago de Tolú Municipality, Sucre Department, for the past 5 years. The case had onset of symptoms on 27 September 2021 and died on 5 October; the case had no history of travel and had an unknown vaccination history. The case was laboratory-confirmed (positive for Corynebacterium diphtheriae by RT-PCR and with the identification of the diphtheria toxin gene).

In the Dominican Republic, between EW 1 and EW 42 of 2021, a total of 56 probable cases of diphtheria were reported, of which 18 were confirmed (14 by laboratory and 4 by epidemiological link) including 12 confirmed deaths (11 by laboratory and one by epidemiological link). Of the total cases reported in 2021, 31 were discarded, one was classified as probable, and 6 remain under investigation. (Figure 1) Information regarding the first 13 confirmed cases reported in 2021 was previously published in the Epidemiological Update on Diphtheria published on 23 April and 25 June 2021.

Among the 18 confirmed cases between EW 1 and EW 42 of 2021, all were of Dominican nationality, 11 were male, ages ranged from 1 to 14 years (median 8 years), all had an incomplete vaccination history, and none reported a recent travel history. Confirmed cases were reported in the provinces of Monte Plata (7 cases including 5 deaths), Santo Domingo (3 cases including 2 deaths), Elías Piña (3 cases including 2 deaths), San Cristobal (2 cases including 1 death), Peravia (1 fatal case), Bahoruco (1 fatal case), and Hato Mayor (1 case). The most recent confirmed case had symptom onset on 9 August 2021 and was reported from Monte Plata Province.

Between EW 1 and EW 42 of 2021, a total of 11 laboratory-confirmed deaths were reported, of which 7 were male and ages ranged from 1 to 14 years old (median 5 years). The most recent fatal case had symptom onset on 27 July 2021 and was reported from Elías Piña Province.

Among the 14 cases for which Corynebacterium diphtheriae was isolated by culture, the results were confirmed by the United States Centers for Disease Control and Prevention (US CDC) as Corynebacterium diphtheriae biovar mitis, toxigenic (diphtheria toxin producer by Elek test).

The diphtheria vaccination schedule in the Dominican Republic includes 3 doses for children under 1 year of age, and 2 boosters which are administered at 18 months and 4 years of age. Vaccination with the third diphtheria booster is not routinely carried out.

The country has a national vaccination policy for health personnel.

The country does not meet the minimum target of 95% vaccination coverage established in the regional immunization action plan for DTP3 for children under 1 year of age. DTP4 coverage is less than 90%.

In Haiti, between EW 32 of 2014 and EW 38 of 2021, a total of 1,334 suspected diphtheria cases were reported, including 147 deaths; of these, 406 cases were confirmed (391 by laboratory and 15 by epidemiological link) including 80 confirmed deaths (Table 1, Figure 2).

Between EW 1 and EW 38 of 2021, the number of suspected cases reported (164 cases) is similar to the number of cases reported during the same period in 2019 (165 cases) but higher than the number of suspected cases reported during the same period in 2020 (110 cases). Among the 164 cases reported, 17 were laboratory-confirmed and one case was confirmed by epidemiological link; there were 3 deaths among the confirmed cases. Considering the prolonged transmission of the disease, diphtheria is considered endemic in Haiti.

Between 2015 and 2021, case-fatality rates among confirmed cases were 23% in 2015, 39% in 2016, 8% in 2017, 13% in 2018, 22% in 2019, 23% in 2020, and 17% in 2021.

Between EW 1 and EW 38 of 2021, among the 18 confirmed cases, 55.5% occurred in the 6 to 14 years age group and 27.7% occurred in the 1 to 5 years age group. Regarding deaths, one occurred in the 6 to 14 years age group and two occurred in the 1 to 5 years age group.

Between EW 1 and EW 38 of 2021, the highest cumulative incidence rates of suspected cases were recorded in the communes of Thiotte (32 cases per 100,000 population) in the South-East Department; Terrier Rouge (20.1 cases per 100,000 population), and Carice (19.2 cases per 100,000 population) in the North-East Department; and Plaine du Nord (19.0 cases per 100,000 population) in the North Department.