- The best point estimate of the population proportion \( p \) is \( \hat{p} = 0.031 \).
- The margin of error \( E \) is \( 0.000 \).
- The 95% confidence interval for the proportion of adverse reactions is \( (0.026, 0.036) \).
Thus, the final boxed answers are:
\[
\boxed{\hat{p} = 0.031}
\]
\[
\boxed{E = 0.000}
\]
\[
\boxed{(0.026, 0.036)}
\]