Is the Omicron subvariant BA.2 more transmissable? | Coronavirus pandemic
Since its emergence in late 2021, Omicron (or BA.1) has quickly become the dominant variant of the COVID-19 virus. The mutations it harboured meant it was more transmissible than the Delta variant, so was able to spread rapidly through populations around the world. It has been found to confer a milder illness than Delta – though milder should not be mistaken for mild.
Scientists are now tracking a subgroup of the Omicron variant, known as BA.2, which was first identified in India and South Africa in late December 2021. Since then, it has been found in the US and Europe. The subvariant is thought to have 20 additional mutations on its spike protein compared with BA.1, though scientists are not quite sure what this will mean for the course of the pandemic. So far, there is insufficient evidence to determine whether BA.2 causes more severe illness than BA.1.
The reason why some people refer to BA.2 as the “stealth” variant is because they claim it is not as easy to detect on PCR and lateral flow tests. This is in fact not true; it can be detected on both types of tests.
PCR tests look for three different DNA sequences when detecting the SARS-CoV-2 virus and will show a positive result if at least two sequences are present. One of the sequences the test looks for is the S-gene, which is found on the spike protein. This is absent in the BA.1 Omicron variant and is known as the “S-gene dropout”; PCR tests will still return a positive result as they will detect the other two DNA sequences they are designed to pick up. But the absence of the S-gene means it was easy for scientists to differentiate between BA.1 Omicron and Delta, which had the S-gene present. Like Delta, the BA.2 Omicron variant has the S-gene present, so it is harder for scientists to tell the difference between BA.2 and Delta, hence the term “stealth” variant. But in another way, this might actually work in our favour: with Omicron now dominant and Delta quickly disappearing, any PCR tests that detect the presence of the S-gene going forward are likely to be the BA.2 subvariant of Omicron.
This variant has become dominant in Denmark. The speed at which cases have risen there and in other countries like the UK suggests that BA.2 may be more transmissible and able to outcompete the BA.1 variant. A recent study looked at the transmission of Omicron subvariants in Danish households and found that the BA.2 subvariant is substantially more transmissible than the original variant.
The study looked at households in Denmark who had one person test positive for Omicron between December 20, 2021 and January 11, 2022. They had 2,122 people who were positive with BA.2 and 6,419 people with BA.1. The researchers then followed these people to see if they passed on their subvariants of Omicron to other members of their household. They found that the BA.2 subvariant transmitted more in both unvaccinated and vaccinated members of the household when compared with the BA.1 subvariant. But they also found that people who were unvaccinated were more likely to transmit BA.2 than those who were vaccinated.
Eric Topol, an American cardiologist and scientist, and founder of the Scripps Research Translational Institute, said about the study that the BA.2 variant findings suggest triple vaccination protects well against symptomatic infection, but he also warned that the increased transmissibility will likely prolong the Omicron wave in some places.
The BA.2 lineage does not appear to cause more severe disease, so there is no reason to panic. It is important to note that it is not unusual to have subgroups of the same variant – that is the nature of a virus that is able to mutate and which has as many human hosts as Omicron does. Vaccines still offer protection against serious illness and, according to the study, also protection against transmission, so it remains important to take them up when offered.
Personal Story: The UK government’s U-turn on NHS COVID vaccine mandate
There has been much debate in recent weeks over the UK government’s decision to mandate COVID-19 vaccines for all National Health Service (NHS) workers come April 1, 2022. Sajid Javid, the country’s health secretary, stated it was the “duty” of NHS staff to get vaccinated, arguing it would keep them and their patients safe.
But with an estimated 77,000 NHS workers unvaccinated, the government decided to back down.
Javid told the Health and Social Care Select Committee that it was right to “reflect” on the policy now that the Omicron variant had surpassed Delta, which was the dominant variant when the policy was initially announced. The government is now considering removing the vaccine mandate for NHS workers.
Many who feel strongly that vaccine mandates are a breach of their human rights will be rejoicing at this U-turn, but some people who are clinically extremely vulnerable and may require treatment from potentially unvaccinated NHS workers have been contacting me via social media to express their dismay at the decision, with one saying that after the UK had all but removed social distancing measures and mask-wearing, this was the “final straw” for her and she felt “abandoned” by policymakers.
I feel everyone offered the vaccines should take them up, and I am triple vaccinated myself, but I have always maintained that getting any medical intervention, including the COVID-19 vaccines, should be a choice. Technically, the choice over having the vaccines was not removed here, but the consequences of not being vaccinated meant potentially becoming unemployed. The NHS is facing what is probably the most difficult time in its history, with a backlog of people needing treatment and staff suffering from burnout. Losing 77,000 staff members would not be in the best interest of patient care and would only lead to further delays and added pressure on the vaccinated staff members left behind.
Despite the U-turn, the initial decision to mandate vaccines for NHS workers has caused considerable stress to those who chose not to take up the vaccines. I have spoken with one healthcare assistant who was in tears after receiving a letter from her hospital telling her she faced disciplinary proceedings and dismissal if she did not take up the vaccines as per government guidelines. She was so upset by this that she took time off work due to the stress it caused. NHS employers were also put in a tough position, forced into difficult conversations with their employees, who are often also their colleagues, that sometimes had a negative impact on their working relationship.
Could all of this have been avoided? In my opinion, yes. Often those in ivory towers make decisions without consulting those of us working on the front line. Many of us know that forcing people to take up vaccines only serves to marginalise them further, and often re-enforces their belief that they are being coerced into having an intervention they feel uneasy about for many reasons.
Education has always been key when it comes to vaccines. Most people I have spoken to have read misinformation online about the vaccines, and by having open and honest conversations with them, we can provide them with the correct information so that they can make an informed choice. The vaccines are not without their small risks, but the benefits they offer against serious illness from COVID-19 far outweigh these risks and that is why I chose to take up mine.
