There was really only one word that dominated the health service this year - Covid-19.

For a second year in a row, the impact of the pandemic was enormous on people, patients, the health service, staff and Government.

But there was also huge controversy over the future of the Sláintecare health reforms and the HSE was hit by a massive cyber attack.

January saw the worst level of Covid-19 cases in hospital and in ICU. This was the third wave of coronavirus, driven by the dominant Alpha variant at the time, which had emerged in the UK a few months earlier.

The HSE test and trace system was under immense pressure. Indeed it was overwhelmed at one point, when on a single day over 8,200 cases were reported. This included a backlog of cases.

At one point there were 2,020 patients with Covid-19 in hospital and 220 in ICU. Such was the pressure on the health service that the HSE issued an unprecedented directive to halt all non-emergency care.

If projections come to pass with the Omicron variant, we could see an even greater pressure on the health system in early January.

For patients, the January pause on non-urgent care meant even longer waiting lists. However some support was provided by private hospitals under an unprecedented deal with the State.

By the end of the year, there were more people than ever waiting to be seen at an outpatient clinic for the first time, or waiting for an operation or procedure.

Alpha was replaced by Delta as the dominant variant as the year progressed, with the first Delta cases seen here in April. The lockdown which came into force at Christmas 2020 was long and hard but was deemed essential to protect the health system.

In mid-April, an easing of Level 5 restrictions saw people permitted to travel within their county and fully vaccinated people to meet other fully vaccinated people indoors.

It was also the year of restrictions on international travel and mandatory hotel quarantine. On 19 July, international non-essential travel was permitted again, once people had the EU Digital Covid Certificate.

The big difference between 2021 and the previous year was the national vaccination programme. It got under way in earnest in January. It was slow at first, dependent on vaccine supplies which were haphazard.

The National Immunisation Advisory Committee (NIAC) became almost as well known as NPHET and advised on which vaccines should be given to various age groups and people with underlying conditions.

The HSE and the public had to wait for official approval by NIAC of vaccine use, some time after they were approved by the European Medicines Agency. These complex recommendations proved a bit of a headache for the HSE, as it had to adapt its plans accordingly. By year end there had been 17 changes to the national vaccination programme.

There was also public and political disquiet when some groups of people were discovered to have been vaccinated out of sequence. One particular case involved the private Beacon Hospital in Dublin, which used leftover vaccines to immunise a number of teachers and staff at a private school in Bray.

A review into the Coombe Hospital also found that a doctor had used leftover vaccines to immunise some family members.

In the end, the national vaccination programme powered ahead and now over 94% of eligible adults have been fully vaccinated. The booster campaign got under way late in the year and plans are in place to vaccinate five to 11-year-olds, with this beginning in earnest in January.

On 14 May, the HSE was hit by an unprecedented ransomware attack and had to shut down all of its systems.

The Department of Health faced a similar IT attack and closed its IT systems. While the impact on the health service was enormous, the national vaccination programme was not affected.

An independent report by PWC published in December concluded that the cyber attackers who hacked the HSE's IT system had accessed the system eight weeks before it detonated the malicious software.

It also found that the HSE was operating on a frail IT system and did not have proper cyber expertise or resources.

In September, the Government's major health reform plan, Sláintecare, faced a massive setback when two top people quit. Laura Magahy, the Executive Director, and Professor Tom Keane, Chairperson of the Slaintecare Implementation Advisory Council, resigned over discontent with the progress of reforms.

Members of the Sláintecare Implementation Advisory Council (SIAC) also went public about their concerns, calling on the Government to ensure the reforms were implemented in deed and spirit. One of the big issues was the delay in putting in place six largely autonomous regional health authorities (RHAs).

In response to claims of resistance by the health service to change, Minister for Health Stephen Donnelly said the latest progress report on the reforms had found that of 112 targets, the majority were on target, or being progressed.

The term of the SIAC was allowed to lapse without renewal and new groups were set up to progress the plans. The 10-year Sláintecare plan promises a single-tiered health system and an end to private practice in public hospitals. It also promises free GP and hospital care. The overall investment is to be €2.8 billion plus a once off capital investment of €3 billion.

By early October, there were very hopeful signs that the impact of the Delta variant was waning and the country was on course for a full reopening from 22 October, also dubbed Freedom Day. But it was not to be.

Cases began to rise again and a return to working from home was advised.

The first official case of the Omicron variant of concern was detected in December and more cases followed. The HSE said it expected this variant to become dominant.

NPHET shocked the Government with tough new recommendations on restrictions, including a 5pm closure for hospitality. The Cabinet eased that to an 8pm time limit.

By 19 December, Omicron had become the dominant strain in Ireland and the projections for the weeks into the new year were grim.

The year ended, on a very familiar, extremely cautious note, with great uncertainty as to what kind of virus spread might be seen during the Christmas and New Year festivities.