The people who contracted COVID-19 had only received their first dose. It takes 8 to 10 days to develop immunity.
On social media, there have been claims about hundreds of Israelis getting infected with COVID-19 after receiving the Pfizer/BioNTech vaccine. The claim implies that the vaccine does not work against the virus. However, this claim is missing key context.
On January 1, 2021, the Times of Israel reported that, of the nearly one million people who had received the Pfizer/BioNTech vaccine in Israel, 240 people had been diagnosed with the virus days after getting the first shot. It further reported that "studies of the vaccine so far have shown immunity to the virus rises only some 8-10 days after the first injection, and then only to around 50 percent effectiveness." It is important to note that the Pfizer vaccine is a two-dose vaccine. The second dose "strengthens the immune system’s response to the virus, bringing it to 95% effectiveness and ensuring that immunity lasts. This level of immunity is only reached about a week after the second dose — or 28 days after the first.
According to a Forbes article from January 27, "Israel released preliminary data on the effects of vaccination for infection. Early indications suggest that after vaccination, as many as 70% of people can still be infected by SARS-CoV-2 after the initial dose of the Pfizer vaccine. More data is needed to confirm the effects on transmissibility among the vaccinated." This data was published in a study that is yet to be peer-reviewed.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.