In many people, antibodies which help to eliminate coronavirus decline to undetectable levels within 60 days of onset of symptoms. Figure source: Medrxiv
The media reacted with horror. This finding suggested that the immune system may forget how to tackle coronavirus just months after an initial infection, meaning a person could become repeatedly unwell and pass on the virus. This would also spell bad news for vaccine trials as triggering immune memory of viruses and bacteria is the basis of vaccination . Our immune systems must remember how to eliminate the virus after vaccination to stop us falling ill from it again.
But the good news is that antibodies are just one component in the complicated system which equips us with long-term immunity to diseases. The cells which produce these antibodies and allow your immune system to react rapidly to bugs that have made you sick in the past are called memory B cells and memory T cells, and these can survive for decades after exposure to some diseases (e.g., measles).
Evidence now shows that coronavirus-specific memory T cells are detectable in the blood after coronavirus infections, and in some studies these memory cells could be detected in people without symptoms.
It is too early to know how long a person is immune to coronavirus after an initial infection, but this data showing that coronavirus memory T cells do exist gives me hope that these cells could persist longer than the coronavirus antibodies analysed in the above-mentioned study.
I remain optimistic that gaining long-term immunity to coronavirus may be possible, but only time will tell.
Months of working from home and being separated from loved ones has inevitably tested our emotional endurance. I think it’s crucial to answer one question to ward off lockdown/social distancing fatigue: was lockdown really worth it? Well, new data from Italy answers this question with a resounding yes.
Northern Italy saw coronavirus cases soar in March and so it was hoped that lockdown would prevent its spread to other regions. A survey carried out by Italy’s Health Ministry and National Statistics Agency has highlighted clear regional differences in the proportion of people who have coronavirus antibodies. In Lombardy in Northern Italy, 7.5% of the population were estimated to be positive for antibodies, compared with only 0.3% in Sicily in Southern Italy.
This proves that their lockdown was effective in stopping the spread of the virus from the centre of the outbreak in Northern Italy to the rest of the country. Also, while Lombardy imposed lockdown when the coronavirus outbreak in the region was well established, lockdown in Sicily was imposed when there were very few cases in the region and this early lockdown clearly prevented more people from contracting the virus.
Ultimately this shows that our efforts to adhere to lockdown rules in the UK have not been in vain. In addition, a recent outbreak in Herefordshire was successfully contained through strict testing and self-isolation procedures.
I feel reassured that we are now better equipped to respond to local outbreaks than earlier this year.