A new study suggests those who recovered from covid-19 infection have much higher immunity to the delta variant than vaccinated people. I have been wondering why there has been very little discussion regarding those who had recovered from covid-19 infections. There is data showing that those who were vaccinated were more resistant to severe infection, but what about those who did covid-19 the hard way; by becoming infected. In my case, I was infected last December and recovered. I found out weeks later I had a strong antibody response and then received the Pfizer vaccine at the beginning of May. While the date in the US has not been openly shared with the public, The Times of Israel recently reported that an unpublished study by Maccabi Healthcare Service looked at individuals who had either gotten two shots of the vaccine by the end of February or tested positive for COVID-19 by that time. It compared 46,035 Maccabi members who caught the coronavirus at some point during the pandemic and the same number of double-vaccinated people. People who had two vaccine shots had a six-fold higher chance of getting infected with Delta than patients who hadn’t been vaccinated but previously contracted the coronavirus, according to the research. The study stated that in the two groups, there were 748 cases of SARS-CoV-2 breakthrough infections, 640 of which were in the vaccinated group and 108 in the previously infected group, which was relying on natural immunity alone. The study does not suggest people forgo vaccination which reduces the risk of severe disease markedly. On the other hand, the study also had shown that those who recovered from a covid-19 infection had a marked boost in immunity. The study does not take into account booster shots that have recently rolled out throughout Israel. This study was published online but has not been peer-reviewed. It is likely that these results clash with the two-shot regimen that is most common in the USA since one shot of any of the vaccines was likely all that was needed for immunity. I had seen this protocol used in other countries as well with good results. What does this mean to you? If you were vaccinated, you have immunity to the Delta variant but breakthrough infections can occur resulting in a milder infection. If you haven’t done so, get vaccinated since it reduces risk. Moderna vaccine appears to offer better longer-term immunity to delta variant than Pfizer does and is a better booster in its current formulation. If you had covid-19 even months ago, you are 6 x less likely to get infected than those who only had the vaccine. If you had been vaccinated and then had a breakthrough infection, you now are even more immune to delta variant and that immunity is likely stronger and more effective than before. Natural covid-19 immunity appears to stay strong even months later compared to vaccine immunity. Breakthrough infection likely eliminates the need for a booster unless a markedly different variant poses a significant risk to the general population that already has immunity. Although in the US, two-shot regimens of Pfizer and Moderna have been required as one size fits all other than the J and J vaccine which recently reported a booster two months later improved its effectiveness to 94%, Those who were already infected may only need one dose for significant effective immunity to future breakthrough infections which was reported months ago even though in the USA, we require two-shot regimens. Although this has not been formally published or peer-reviewed, the findings are likely valid and there will be other studies looking at this in the future.