UK-designed algorithm the cause of erroneous vaccine invites

Wednesday 17 March 2021

An algorithm designed to identify those with underlying health conditions has led to some islanders being offered a vaccine ahead of time, with authorities admitting that the "anomalies" could also result in some people with medical issues being missed off the priority list.

Express has received numerous calls in recent days from islanders with no known medical worries who have been offered a vaccine as part of Group 6, and from others who are awaiting their invite.

The cohort is meant to be reserved for people with underlying health conditions 'which put them at higher risk of serious disease and mortality' than the average person. 

Around 10,000 people under the age of 65 have been identified as falling into this category, while people considered to be 'extremely clinically vulnerable' have already received their first jab.

However, an unspecified number of islanders placed in the Group 6 cohort have since been deemed 'low risk' individuals. 

Health & Social Care has chalked the issue down to the various different ways that medical data is stored by health and care practitioners. A spokesperson also stated that the algorithm was built around NHS databases and had not translated perfectly to the way records are collected locally. 

"The algorithm does not apply clinical discretion in the same way a health professional might do, and instead highlights individual solely on the information available by searching for certain flags, or codes," said the spokesperson. 

Pictured: The Bailiwick's Vaccination Programme recently progressed to cohort 6, which amounts to around one-sixth of Guernsey's population. Everyone in this group should receive a vaccination offer before the end of the month. 

"By combining data from different sources, the algorithm – which was designed based on NHS databases and when applied against the various local databases used across primary and secondary care may present some anomalous results."

HSC say this "only occurs in only a small number of cases", resulting in some people being offered a vaccine out of sync and others, potentially, falling through the cracks. 

"We know using this algorithm could result in some people being missed or, as we know has happened, some people who are actually at low risk will end up jumping the queue," the spokesperson said.

"But we need to focus on the positives of the situation we find ourselves in especially in the context of us entering the third consecutive week with no new cases. An algorithm is able to search through data far more quickly than any human ever could."

"If we chose to, we could wait to push out this vaccine to medically at risk cohorts until the coding of every single medical record of all patients registered with a GP practice had been assessed and considered accurate.

"But that decision would cause a significant delay to the roll out of the vaccine programme and would be extremely costly. We are currently on schedule to ensure that everyone in priority groups 1 to 9 will have received their first dose of vaccine by 8 May 2021 and, for the benefit of our community, we would not wish to delay this unnecessarily."

Pictured: Health services have given reassurances that the States of Guernsey "has not been given any of your private medical information" from people's primary health care practices.

HSC said there are numerous reasons why someone may be offered a vaccine unexpectedly early.

"It could be that many years ago you were prescribed some medication for something that has led to you being identified within the database as higher risk," said the spokesperson. "This is nothing to worry about, especially if you don’t think of yourself as higher risk."

None of the invitations are going to be revoked, HSC confirmed, as it asked islanders to "please take the opportunity to have your vaccine."