While the reinfection rates are less than 1% and a rare occurrence, the CDC still asks recovered and vaccinated individuals to wear masks out of an abundance of caution. We'll learn more about where these numbers come from, what the CDC recommendations are, and highlight what Dr. Fauci thinks about the rate of reinfection.
By March 8th, 2021 more than 31 million people or about 9.4% of the US population completed a vaccination series. On March 10th, the CDC released its first public health recommendation for fully vaccinated individuals who are at least 2 weeks out from the 2nd and final dose (Pfizer-BioNTech or Moderna) or from the first and only dose (Janssen single-dose vaccine). For those wondering, the first dose of the mRNA vaccine is only about 50-60% effective which is why a second dose is needed.
The most up to date recommendations are published on the CDC website here and shown below.
What is confusing to the public is why a vaccinated person would ever need to wear a mask anymore? The CDC is overly cautious because of the assumption that vaccinated individuals can still get infected and transmit this infection to others albeit at a much lower transmission risk. This lower transmission risk is because of a much lower viral load during an infection than someone who is not vaccinated and has not formed the antibodies needed to decrease or neutralize the virus. Let's dig a little deeper here.
For the main SARS-CoV-2 variant: Multiple studies from the US, UK, and Israel found that 2 doses of the Pfizer-BioNTech or Moderna Vaccine was 86-92% effective. For comparison, the flu vaccine that we get every year is about 40-60% effective according to the CDC but really closer to 40% in the past 5 years. The measles vaccine on the other hand is 99.7% effective.
Note on the math here: Effective here means the percent reduction in infection compared to a non-vaccinated person. Let's say that without a vaccine I have a 50 percent chance of becoming infected, but with the vaccine my chance of being infected is dropped to 5 percent then it is 90% effective.
For other SARS-CoV-2 variants: New variants have sprung up--some with mild resistance to the vaccine such as the B.1.1.7 (UK) and B.1.427 & B.1.429 (US California) variants, while others have shown significant resistance to the vaccine such as the B.1.351 (South Africa) variant which was first confirmed in a Connecticut resident on February 15th, 2021. Note that the widely reported 'significant' resistance has been anecdotal and has not been properly evaluated yet.
What about individuals who were infected then recovered from Covid-19? Some studies have shown that the level of antibody neutralizing activity was still higher in vaccinated individuals (>90% protection) compared to people who recovered from COVID-19 (>75% protection). In one UK study called SIREN found that 0.67% of recovered patients were probably reinfected (exact wording used in the study) based on a positive PCR detection of virus at least 90 days from the first infection. This rare occurrence was confirmed by the Statens Serum Institut in Denmark that found a reinfection rate of 0.65% from more than 4 million patients who were previously infected and had were later found to have a positive repeat PCR test. An analysis of the sub-population of healthcare workers only found their reinfection rate at 1.2%. In comparison with individuals who received two doses of the vaccine, we are starting to see new data coming in. The department of Public Health in Louisville Kentucky found a reinfection rate of 0.013% out of 47,000 people vaccinated.
Does that mean that people who recovered from Covid-19 should still get vaccinated? The CDC recommends that yes they should still get vaccinated (out of an abundance of caution most likely). Since a few studies have shown that reinfection is low in the first 90 days, the CDC does not recommend repeat testing or quarantine of a recently infected individual for those 90 days. Keep in mind, other studies show SARS-CoV-2 antibodies can last for at least 6+ months in recovered patients, so the focus on 90 days is a conservative approach. In this case, the single dose Janssen dose would be suitable to top off your antibody level 90 days after infection.
Will vaccinated individuals be required to get vaccinated again or recieve a booster shot? The short answer is yes but we await new studies to tell us how long we can wait. Thus far, studies from other coronaviruses such as the SARS-CoV-1 and MERS-COVID show immunity lasting between 12-34 months.
As promised, we're sharing the video where Senator Rand Paul questions Dr. Fauci on the need for the mask mandate which he calls "theater" with such low reinfection rates. Dr. Fauci clarified that the mask mandate is important to protect against the new variants. The important note here is that we really don't know enough about the reinfection rate with new variants for recovered or vaccinated patients and Dr. Fauci has a more cautious and conservative approach to public health policy of assuming the worst until proven otherwise.