The Ministry of Health will not publish a count of whooping cough cases in Cayman. The Ministry of Health, Environment and Sustainability (MHES) told The Caymanian Journal (TCJ) on 24 September that results from the on-island laboratory "cannot be considered a complete national case count" because testing may also be done at other laboratories, including overseas, and laboratories "are not currently required by law to report results directly to Public Health".

Doctors are. The Public Health Act lists whooping cough among the notifiable diseases that every medical practitioner attending a patient must certify "forthwith" to the Senior Medical Officer of Health, a duty that does not depend on which laboratory ran the test. The Ministry's 24 September response did not address notifications by medical practitioners.

The Ministry also said Public Health "does not currently characterise the situation as an outbreak", the term it used in its 11 June statement, and now assesses "low-level circulation of pertussis within the community". Chief Medical Officer Dr Hilary Wolf said the majority of cases seen had been mild. The Ministry declined to give a breakdown of cases by age, the number of hospital admissions, or the number of schools and nurseries in which cases have been found.

The answers came three days after the Ministry and the Public Health Department said on 21 September that pertussis cases "continue to be identified in the Cayman Islands", five months after the first confirmed case at a Grand Cayman high school on 27 April 2026. None of the four public statements, on 27 April, 6 May, 11 June and 21 September, has given a figure. The Ministry said on 24 September that its communications would continue to focus on "the assessed level of public-health risk and the actions residents should take, rather than providing a running tally of cases".

"While the majority of cases we have seen with pertussis have been mild, pertussis is an illness we need to take seriously, particularly because of the risk it can pose to babies who are too young to be fully vaccinated," Wolf said in the Ministry's written response. She asked parents to check that teenagers had received the Tdap booster recommended at 14. "As children get older, routine vaccinations can sometimes be overlooked, so this is a good opportunity for families to check their records," she said. Pregnant women should speak to their healthcare provider or Public Health about Tdap in pregnancy, which she said protects newborns in their first months.

The Ministry gave a reason for each figure it withheld. On hospital admissions and intensive care it said: "As this is a small community, providing information at this level of detail could potentially allow individual patients to be identified." During the COVID-19 pandemic the Ministry published daily counts of hospital admissions in the same community. On the age breakdown it said Public Health collects demographic and clinical information for surveillance and uses it to assess risk and shape its response, adding that infants too young to be fully vaccinated are at greatest risk of serious illness. On schools and other settings it said Public Health follows up with affected individuals and settings and decides case by case whether broader public notification is needed.

The Ministry contrasted its approach with the COVID-19 pandemic, when it said regular case counts were "an important tool for monitoring and communicating the trajectory of a novel disease". For pertussis, it said, "laboratory-confirmed cases do not provide a complete measure of community circulation because not every infection is recognised, tested or confirmed". That is true of every surveillance system. The UK Health Security Agency publishes laboratory-confirmed pertussis counts for England every quarter, broken down by month and by age group, with the caveat that the figures are provisional and understate the number of infections; it continued to do so through England's surge of cases in 2024.

On its use of the word "outbreak" on 11 June, the Ministry said the terminology "reflected the information available at that stage" and that assessments are updated as surveillance information comes in. The 11 June statement, issued by the Ministry and the Public Health Department, also said disease activity at that time did not indicate widespread community transmission and that cases were being seen "particularly among infants who are not yet fully protected through vaccination".

Testing for pertussis in Cayman is done at the Health Services Authority's Cayman Islands Molecular Biology Laboratory on a respiratory panel that covers 22 pathogens. The Ministry said the panel was brought online in 2023; its written response to TCJ on 24 September had given 2022, and it corrected the date in a further email the same day. It said that demand took "a few years" to build, with the volume of tests increasing substantially in the past year. Before the panel was in use, it said, clinicians would have had to send a specific sample to a laboratory on suspicion of pertussis, "which likely would've missed many mild cases in adolescents and adults". More testing finds more mild cases, which is the Ministry's strongest argument for caution in reading any count, and the reason other health authorities publish counts with that caveat attached rather than withhold them.

The Public Health Department will hold two further walk-in vaccination clinics for children and adults who need a pertussis-containing vaccine or booster, on Saturday 26 September and Saturday 10 October 2026, from 9am to 1pm at the Public Health Clinic on the second floor of the Smith Road Medical Centre. Three earlier Saturday clinics were held on 20 June at Smith Road, 11 July at West Bay Health Centre and 8 August at Bodden Town Health Centre, according to the 11 June statement. The Ministry has not said how many doses were given at them. Children receive pertussis-containing vaccines at two, four and six months, with boosters at 18 months and four years and a Tdap booster at 14, according to the schedule in the 21 September statement.

Early symptoms resemble a cold: a runny nose, low-grade fever and a mild or occasional cough. After one to two weeks the cough can become severe, with repeated or prolonged fits, vomiting after coughing, difficulty catching breath, or a "whooping" sound on breathing in. The Ministry said the whooping sound does not occur in everyone and the cough can last several weeks. Parents are asked to keep children home when unwell, particularly with a persistent or worsening cough, and adults with respiratory symptoms are asked to do the same. The 11 June guidance says anyone diagnosed should stay away from school, work, childcare and public settings "for up to 21 days until they have completed the recommended antibiotic treatment".

TCJ put eight questions to the Ministry in writing on 21 September and received its response on 24 September, after two requests for more time to confirm its figures. The Ministry said it would "continue to provide information necessary to keep the public informed about the level of risk and any actions they should take".

Eight questions, what was answered

TCJ emailed the Ministry of Health, Environment and Sustainability on 21 September. Its written response arrived on 24 September.